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Sample records for quasi-one-dimensional organic conductor

  1. Electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ

    DEFF Research Database (Denmark)

    Sing, M.; Schwingenschlögl, U.; Claessen, R.;

    2003-01-01

    We study the electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ by means of density-functional band theory, Hubbard model calculations, and angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant quantitative and qualitative...

  2. Inhomogeneous superconductivity in quasi-one dimensional organic conductors and ropes of carbon nanotubes

    Science.gov (United States)

    Bellafi, B.; Haddad, S.; Sfar, I.; Charfi-Kaddour, S.

    2009-03-01

    It has been reported that, in quasi-one dimensional organic conductors, superconductivity may coexist macroscopically with non-superconducting states giving rise to an inhomogeneous phase. We investigate, based on the time-dependent Ginzburg-Landau theory, the effect of disorder on the stability of the superconducting phase in such a mixed state. We also focus on the interplay between superconductivity and disorder in ropes of carbon nanotubes. We show that the superconducting transition temperature in quasi-one organic conductors is reduced by disorder but does not obey the Abrikosov-Gorkov law. However, and contrary to what is expected, disorder can further superconductivity in ropes of carbon nanotubes.

  3. Spectroscopic signatures of spin-charge separation in the quasi-one-dimensional organic conductor TTF-TCNQ

    DEFF Research Database (Denmark)

    Claessen, R.; Sing, M.; Schwingenschlogl, U.;

    2002-01-01

    The electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ is studied by angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant discrepancies to band theory. We demonstrate that the measured dispersions can be consistently mapped onto...... the one-dimensional Hubbard model at finite doping. This interpretation is further supported by a remarkable transfer of spectral weight as a function of temperature. The ARPES data thus show spectroscopic signatures of spin-charge separation on an energy scale of the conduction bandwidth....

  4. Field-Induced CDW Phases in a Quasi-One-Dimensional Organic Conductor, HMTSF-TCNQ Under Pressure of 1 GPa in Magnetic Field of 31 T

    Science.gov (United States)

    Murata, K.; Kang, W.; Masuda, K.; Fukumoto, Y.; Graf, D.; Kiswandhi, A.; Choi, E. S.; Brooks, J. S.; Sasaki, T.; Yokogawa, K.; Yoshino, H.; Kato, R.

    2013-03-01

    HMTSF-TCNQ is a quasi-one-dimensional organic conductor which undergoes CDW(charge density wave) transition at 30 K at ambient pressure, where HMTSF-TCNQ is hexamethylenetetraselena fulvalene-tetracyano quino dimethane. This CDW is suppressed by the pressure of 1 GPa. At this pressure, we found field-induced successive hysteretic transitions in magnetoresistance. This reminds us of the successive field-induced SDW (spin density wave) phases in TMTSF2X salts. However, the field range of interest is 2-3 times higher than that of TMTSF2X salts. Therefore, we need really high field to examine these properties. It is very likely that the field induced phases are of field induced CDW (FICDW), where quantum Hall effect and many interesting phenomena are expected like in the case of FISDW. Together with the magnetoresistance study up to the field of 31 Tesla and at temperatures down to 0.4 K in various magnetic field angles respective to the crystal axes, we examined the angular dependence of magnetoresistance oscillations(AMRO). It turned out that AMRO demonstrates clearly the occurrence of field-induced phase rather than the magneto-resistance by field sweep. Since the Hall resistance, R xy in the field-induced phases showed stepwise plateau structure against the field sweep, and its strength was in the order of magnitude of h/ e 2 per molecular sheet, the Hall effect is very suggestive of quantum Hall effect.

  5. Effect of interchain frustration in quasi-one-dimensional conductors at half-filling

    Science.gov (United States)

    Tsuchiizu, M.; Suzumura, Y.; Bourbonnais, C.

    2007-04-01

    We examine the effect of frustrated interchain hoppings t_{\\perp 1} and t_{\\perp 2} on one-dimensional Mott insulators. By applying an N_\\perp -chain two-loop renormalization-group method to the half-filled quasi-one-dimensional Hubbard model, we show that the system remains insulating even for the large t_{\\perp 1} as far as t_{\\perp 2}=0 and vice versa, whereas a metallic state emerges by increasing both interchain hoppings. We also discuss the metallic behaviour suggested in the quasi-one-dimensional organic compound (TTM-TTP)I3 under high pressure.

  6. Electric-Field Effect on the Angle-Dependent Magnetotransport Properties of Quasi-One-Dimensional Conductors

    Science.gov (United States)

    Kobayashi, K.; Saito, M.; Ohmichi, E.; Osada, T.

    2006-03-01

    We report a novel electric field effect on angular dependent magnetotransport in quasi-one-dimensional layered conductors with a pair of sheetlike Fermi surfaces. Under tilted magnetic fields and additional interlayer electric fields, semiclassical electron orbits on two Fermi sheets become periodic at different magnetic field orientations. This causes double splitting of the Lebed’s commensurability resonance in interlayer transport, and the amount of splitting allows us to estimate the Fermi velocity directly. We have successfully demonstrated this effect in the organic conductor α-(BEDT-TTF)2KHg(SCN)4.

  7. Finite-size effects in quasi-one-dimensional conductors with a charge-density wave

    Energy Technology Data Exchange (ETDEWEB)

    Zaitsev-Zotov, Sergei V [Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Moscow (Russian Federation)

    2004-06-30

    Recent studies of finite-size effects in charge-density wave conductors are reviewed. Various manifestations of finite-size effects, including the transverse-size dependence of the nonlinear-conduction threshold field, the Peierls transition temperature, high-frequency conduction, and the relaxation rates of metastable states, are discussed. Resistivity jumps in thin samples, the smeared threshold field for nonlinear conduction, and threshold conduction above the Peierls transition temperature are considered, as are mesoscopic oscillations of the threshold field, one-dimensional conduction in thin crystals, absolute negative conductivity of quasi-one-dimensional conductors, the length dependence of the phase-slip voltage, and the Aharonov-Bohm oscillations in sliding CDWs. Problems yet to be solved are discussed. (reviews of topical problems)

  8. Quantum Hall Effect in Quasi-One-Dimensional Conductors: The Roles of Moving FISDW, Finite Temperature, and Edge States

    Science.gov (United States)

    Yakovenko, Victor M.; Goan, Hsi-Sheng

    1996-12-01

    This paper reviews recent developments in the theory of the quantum Hall effect (QHE) in the magnetic-field-induced spin-density-wave (FISDW) state of the quasi-one-dimensional organic conductors (TMTSF)2X. The origin and the basic features of the FISDW are reviewed. The QHE in the pinned FISDW state is derived in several simple, transparent ways, including the edge states formulation of the problem. The temperature dependence of the Hall conductivity is found to be the same as the temperature dependence of the Fröhlich current. It is shown that, when the FISDW is free to move, it produces an additional contribution to the Hall conductivity that nullifies the total Hall effect. The paper is written on mathematically simple level, emphasizes physical meaning over sophisticated mathematical technique, and uses inductive, rather than deductive, reasoning.

  9. Growth, crystal structure and transport properties of quasi one-dimensional conductors NbS{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zybtsev, S.G., E-mail: zybt@cplire.ru [Kotel' nikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11-7, Moscow125009 (Russian Federation); Pokrovskii, V.Ya.; Nasretdinova, V.F.; Zaitsev-Zotov, S.V. [Kotel' nikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11-7, Moscow125009 (Russian Federation)

    2012-06-01

    We report synthesis of quasi-one-dimensional conductor NbS{sub 3}, TEM studies and transport properties of the prepared samples. The grown NbS{sub 3} whiskers are Peierls conductors known as phase II with the transitions at T{sub P1}=365 K and T{sub P2}=150 K. CDW1 is stable and not so sensitive to growth conditions. It can slide and be synchronized by the external microwave irradiation up to 16 GHz. CDW2 strongly depends on growth conditions. Nevertheless, it also shows sliding and synchronization.

  10. Superconducting pairing and density-wave instabilities in quasi-one-dimensional conductors

    Science.gov (United States)

    Nickel, J. C.; Duprat, R.; Bourbonnais, C.; Dupuis, N.

    2006-04-01

    Using a renormalization group approach, we determine the phase diagram of an extended quasi-one-dimensional electron gas model that includes interchain hopping, nesting deviations, and both intrachain and interchain repulsive interactions. d -wave superconductivity, which dominates over the spin-density-wave (SDW) phase at large nesting deviations, becomes unstable to the benefit of a triplet f -wave phase for a weak repulsive interchain backscattering term g1⊥>0 , despite the persistence of dominant SDW correlations in the normal state. Antiferromagnetism becomes unstable against the formation of a charge-density-wave state when g1⊥ exceeds some critical value. While these features persist when both Umklapp processes and interchain forward scattering (g2⊥) are taken into account, the effect of g2⊥ alone is found to frustrate nearest-neighbor interchain d - and f -wave pairing and instead favor next-nearest-neighbor interchain singlet or triplet pairing. We argue that the close proximity of SDW and charge-density-wave phases, singlet d -wave, and triplet f -wave superconducting phases in the theoretical phase diagram provides a possible explanation for recent puzzling experimental findings in the Bechgaard salts, including the coexistence of SDW and charge-density-wave phases and the possibility of a triplet pairing in the superconducting phase.

  11. Surface characterization and surface electronic structure of organic quasi-one-dimensional charge transfer salts

    DEFF Research Database (Denmark)

    Sing, M.; Schwingenschlögl, U.; Claessen, R.

    2003-01-01

    We have thoroughly characterized the surfaces of the organic charge-transfer salts TTF-TCNQ and (TMTSF)(2)PF6 which are generally acknowledged as prototypical examples of one-dimensional conductors. In particular x-ray-induced photoemission spectroscopy turns out to be a valuable nondestructive d...

  12. Giant Peltier Effect in Self-Organized Quasi-One-Dimensional Nano-Structure in Cu-Ni Alloy

    Science.gov (United States)

    Dang Vu, Nguyen; Sato, Kazunori; Katayama-Yoshida, Hiroshi

    2011-01-01

    Based upon ab initio electronic structure calculations by the Korringa-Kohn-Rostoker coherent potential approximation and Monte Carlo simulation of the two-dimensional spinodal nano-decomposition, we simulate the formation of a self-organized quasi-one-dimensional nano-structure (Konbu-Phase) under a layer-by-layer crystal growth condition of Cu-Ni alloy. We propose a new mechanism of the giant Peltier coefficient dramatically enhanced by the one-dimensional singular density of states in the Konbu-Phase in addition to the conventional Peltier cooling and the spin-entropy expansion cooling.

  13. Giant Peltier Effect in Self-Organized Quasi-One-Dimensional Nano-Structure in Cu--Ni Alloy

    Science.gov (United States)

    Vu, Nguyen Dang; Sato, Kazunori; Katayama-Yoshida, Hiroshi

    2011-01-01

    Based upon ab initio electronic structure calculations by the Korringa--Kohn--Rostoker coherent potential approximation and Monte Carlo simulation of the two-dimensional spinodal nano-decomposition, we simulate the formation of a self-organized quasi-one-dimensional nano-structure (Konbu-Phase) under a layer-by-layer crystal growth condition of Cu--Ni alloy. We propose a new mechanism of the giant Peltier coefficient dramatically enhanced by the one-dimensional singular density of states in the Konbu-Phase in addition to the conventional Peltier cooling and the spin-entropy expansion cooling.

  14. Physical Properties of (NH4)2Pt(CN)4[Clo.42].3H2O: A new Quasi-One-Dimensional Conductor

    DEFF Research Database (Denmark)

    Carneiro, Kim; Petersen, A. S.; Underhill, A. E.

    1979-01-01

    to drop, and second, an increased Fermi wave vector kF introduces a change in the electron-phonon coupling constant λ via the bare phonon frequency ω(2kF). Third, the interchain coupling η is enhanced in ACP(Cl), which seems to be related to the hydrogen bonding of the NH4+ ions. We also present......The quasi-one-dimensional conductor (NH4)2[Pt(CN)4]Cl0.42·3H2O, ACP(Cl), has been studied experimentally by means of electrical conduction measurements, x-ray diffuse scattering, and neutron inelastic scattering. This allows the determination of all the physical parameters of interest...

  15. NMR studies of the internal electric field in a single crystal of the quasi-one-dimensional conductor Li0.9Mo6O17

    Science.gov (United States)

    Wu, Guoqing; Wu, Bing

    2015-03-01

    The quasi-one-dimensional (Q1D) conductor Li0.9Mo6O17 is of considerable interest because it has a highly conducting phase with properties likely associated with a Luttinger liquid, a poorly understood ``metal-insulator'' crossover at temperature TMI = 24 K, and a 3D superconducting phase that may involve triplet Cooper pairs at Tc = 2.2 K, while the mechanism for many of its properties has been a long mystery and it presents tremendous experimental challenges. We report the 7Li-NMR measurements of the internal electric field with an externally applied magnetic field B0 = 9 - 12 T, and we also show our theoretically calculated result of the electric field based on the structure of the crystal lattice. We find that the 7Li-NQR frequency (νQ) has a value of ~ 45 kHz and the electric field gradient (EFG) at the Li site due to the charges of the surrounding Mo conduction electrons has an axial symmetry with the principle axis (pz) to be along the lattice a-axis. There is no temperature or field dependence for the value of νQ or EFG, indicating that the ``metal-insulator'' crossover has a magnetic origin, rather than the charge density wave (CDW) as one of the possible mechanisms previously thought in literature.

  16. Spatially confined electron spin diffusion in quasi-one-dimensional organic conductors

    CERN Document Server

    Wokrina, T

    2002-01-01

    After an introduction to the substances and some important properties of them the measurement principle, the time-resolved electron spin resonance is presented. Then the foundations and the technical realization of an image-shaping procedure on the base of electron spin tomography are described. The measurement of the spin dynamics for the three radical-ion salts form the main part and the conclusion of this thesis.

  17. Novel superconducting phenomena in quasi-one-dimensional Bechgaard salts

    Science.gov (United States)

    Jerome, Denis; Yonezawa, Shingo

    2016-03-01

    It is the saturation of the transition temperature Tc in the range of 24 K for known materials in the late sixties that triggered the search for additional materials offering new coupling mechanisms leading in turn to higher Tc's. As a result of this stimulation, superconductivity in organic matter was discovered in tetramethyl-tetraselenafulvalene-hexafluorophosphate, (TMTSF)2PF6, in 1979, in the laboratory founded at Orsay by Professor Friedel and his colleagues in 1962. Although this conductor is a prototype example for low-dimensional physics, we mostly focus in this article on the superconducting phase of the ambient-pressure superconductor (TMTSF)2ClO4, which has been studied most intensively among the TMTSF salts. We shall present a series of experimental results supporting nodal d-wave symmetry for the superconducting gap in these prototypical quasi-one-dimensional conductors. xml:lang="fr"

  18. Strong Electron Correlation in the High-Temperature Phase of (EDO-TTF)2PF6 as a Quasi-One-Dimensional Molecular Conductor

    Science.gov (United States)

    Iwano, Kaoru; Shimoi, Yukihiro

    2010-10-01

    We focus on the electronic property of the high-temperature phase of (EDO-TTF)2PF6. Applying a cluster-based density-functional theory (DFT) calculation augmented by a self-consistent environment, we recognize a strong electron-electron repulsion in a dimer-Mott-type ground state. On the basis of this ground state, we obtain an absorption spectrum that takes a form of a single peak in the mid-infrared (mid-IR) region. We next analyze a Hubbard model with alternate transfers, of which the values are determined by the DFT calculations. The obtained absorption peak energy is comparable to the mid-IR peak energy observed in the experiment. Finally, we also investigate other one-dimensional conductors, (TMTSF)2PF6 and (TMTTF)2PF6, which are known as correlated metals, and conclude that (EDO-TTF)2PF6 also falls in this category, in spite of its unique (0110)-type charge ordering observed in the low-temperature phase.

  19. Topological edge state with zero Hall conductivity in quasi-one dimensional system

    Directory of Open Access Journals (Sweden)

    Xiao-Shan Ye

    2016-09-01

    Full Text Available We explore the structure of the energy spectra of quasi-one dimensional (Q1D system subjected to spin-density-wave SDW states. The structure of the energy spectra opens energy gaps with Zeeman field. Theses gaps result in plateaus for the Quantum Hall conductivity which is associated with edge states. Different from the SSH Hofstadter model, here we show that there are a doublet of edge states contribution to zero Hall conductivity. These edge states are allowed for magnetic control of spin currents. The topological effects predicted here could be tested directly in organic conductors system.

  20. Topological edge state with zero Hall conductivity in quasi-one dimensional system

    Science.gov (United States)

    Ye, Xiao-Shan

    2016-09-01

    We explore the structure of the energy spectra of quasi-one dimensional (Q1D) system subjected to spin-density-wave SDW states. The structure of the energy spectra opens energy gaps with Zeeman field. Theses gaps result in plateaus for the Quantum Hall conductivity which is associated with edge states. Different from the SSH Hofstadter model, here we show that there are a doublet of edge states contribution to zero Hall conductivity. These edge states are allowed for magnetic control of spin currents. The topological effects predicted here could be tested directly in organic conductors system.

  1. New Quasi-One-Dimensional Organic-Inorganic Hybrid Material: 1,3-Bis(4-piperidiniumpropane Pentachlorobismuthate(III Synthesis, Crystal Structure, and Spectroscopic Studies

    Directory of Open Access Journals (Sweden)

    Hela Ferjani

    2014-01-01

    Full Text Available The organic-inorganic hybrid compound (C13H28N2 BiCl5 was synthesized by solvothermal method. The crystal structure was solved by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic system space group Cmc21 with a=15.826(4 Å, b=18.746(6 Å, c=7.470(3 Å, and Z=4. The crystal structure was refined down to R=0.019. It consists of corrugated layers of [BiCl5]2− chains, separated by organic [H2TMDP]2+ cations (TMDP=1,3-Bis(4-piperidylpropane = C13H26N2. The crystal cohesion is achieved by hydrogen bonds N–H⋯Cl joining the organic and inorganic layers. The influence of the organic cations' flexibility is discussed. Raman and infrared spectra of the title compound were recorded in the range of 50–400 and 400–4000 cm−1, respectively. Semiempirical parameter model three (PM3 method has been performed to derive the calculated IR spectrum. The crystal shape morphology was simulated using the Bravais-Friedel and Donnay-Harker model.

  2. Dimethylammonium copper formate [(CH3)2NH2]Cu(HCOO)3: A metal-organic framework with quasi-one-dimensional antiferromagnetism and magnetostriction

    Science.gov (United States)

    Wang, Zhenxing; Jain, Prashant; Choi, Kwang-Yong; van Tol, Johan; Cheetham, Anthony K.; Kroto, Harold W.; Koo, Hyun-Joo; Zhou, Haidong; Hwang, Jungmin; Choi, Eun Sang; Whangbo, Myung-Hwan; Dalal, Naresh S.

    2013-06-01

    Metal-organic frameworks (MOFs) can exhibit many interesting properties such as multiferroic behavior, dipolar glass, gas storage, and protonic conductivity. Here we report that dimethylammonium copper formate (DMACuF) [(CH3)2NH2]Cu(HCOO)3, a cation templated nonporous MOF with perovskite topology, exhibits strong one-dimensional (1D) antiferromagnetism with a Néel temperature, TN, of 5.2 K. These conclusions are derived from detailed magnetic susceptibility, heat capacity, dielectric constant, and high-frequency electron paramagnetic resonance measurements as well as density functional theory (DFT) calculations. The magnetic susceptibility exhibits a broad maximum at ˜50 K, suggesting low-dimensional magnetism; heat capacity measurements show a Néel temperature of 5.2 K. The magnetization versus field data at 1.8 K shows a spin-flop transition at Hsf ˜ 1.7 T. The ratio TN/J=6.5×10-2, where J is the near-neighbor exchange constant (77.4 K), and the small value (2 K) of the interchain coupling suggests that DMACuF is close to an ideal 1D magnet. In this three-dimensional crystal lattice, the 1D magnetic behavior is made possible by the Jahn-Teller distortion of the 3d9 Cu2+ ions. Temperature dependence of the electron paramagnetic resonance field and the linewidth exhibits critical broadening for temperatures below 50 K, following a behavior quite characteristic of 1D spin systems. DFT calculations show that [(CH3)2NH2]Cu(HCOO)3 has a magnetic structure in which 1D antiferromagnetic chains parallel to the c direction are weakly coupled ferromagnetically, supporting the thermomagnetic and EPR results. Dielectric measurements under applied magnetic fields of 0-7 T reveal a kink at the TN, a clear indication of magnetostriction behavior.

  3. Current-Voltage Characteristics of Quasi-One-Dimensional Superconductors

    DEFF Research Database (Denmark)

    Vodolazov, D.Y.; Peeters, F.M.; Piraux, L.

    2003-01-01

    The current-voltage (I-V) characteristics of quasi-one-dimensional superconductors were discussed. The I-V characteristics exhibited an unusual S behavior. The dynamics of superconducting condensate and the existence of two different critical currents resulted in such an unusual behavior....

  4. Quasi-one-dimensional intermittent flux behavior in superconducting films

    DEFF Research Database (Denmark)

    Qviller, A. J.; Yurchenko, V. V.; Galperin, Y. M.

    2012-01-01

    . The intermittent behavior shows no threshold value in the applied field, in contrast to conventional flux jumping. The results strongly suggest that the quasi-one-dimensional flux jumps are of a different nature than the thermomagnetic dendritic (branching) avalanches that are commonly found in superconducting...

  5. Luttinger parameter of quasi-one-dimensional para -H2

    Science.gov (United States)

    Ferré, G.; Gordillo, M. C.; Boronat, J.

    2017-02-01

    We have studied the ground-state properties of para-hydrogen in one dimension and in quasi-one-dimensional configurations using the path-integral ground-state Monte Carlo method. This method produces zero-temperature exact results for a given interaction and geometry. The quasi-one-dimensional setup has been implemented in two forms: the inner channel inside a carbon nanotube coated with H2 and a harmonic confinement of variable strength. Our main result is the dependence of the Luttinger parameter on the density within the stable regime. Going from one dimension to quasi-one dimension, keeping the linear density constant, produces a systematic increase of the Luttinger parameter. This increase is, however, not enough to reach the superfluid regime and the system always remain in the quasicrystal regime, according to Luttinger liquid theory.

  6. Exchange effects in a quasi-one-dimensional electron gas

    Science.gov (United States)

    Gold, A.; Ghazali, A.

    1990-04-01

    We calculate the electron exchange of a quasi-one-dimensional electron gas in a quantum-well wire of radius R0. A two-subband model is considered and the exchange self-energy for the first and second subband is calculated under the assumption that only the lowest subband is partially filled with electrons. Band-bending effects are also discussed. Results for the total energy per electron including kinetic and exchange energy are presented.

  7. Dynamical Structure Factors of quasi-one-dimensional antiferromagnets

    Science.gov (United States)

    Hagemans, Rob; Caux, Jean-Sébastien; Maillet, Jean Michel

    2007-03-01

    For a long time it has been impossible to accurately calculate the dynamical structure factors (spin-spin correlators as a function of momentum and energy) of quasi-one-dimensional antiferromagnets. For integrable Heisenberg chains, the recently developed ABACUS method (a first-principles computational approach based on the Bethe Ansatz) now yields highly accurate (over 99% of the sum rule) results for the DSF for finite chains, allowing for a very precise description of neutron-scattering data over the full momentum and energy range. We show remarkable agreement between results obtained with ABACUS and experiment.

  8. Fourier's law for quasi-one-dimensional chaotic quantum systems

    Science.gov (United States)

    Seligman, Thomas H.; Weidenmüller, Hans A.

    2011-05-01

    We derive Fourier's law for a completely coherent quasi-one-dimensional chaotic quantum system coupled locally to two heat baths at different temperatures. We solve the master equation to first order in the temperature difference. We show that the heat conductance can be expressed as a thermodynamic equilibrium coefficient taken at some intermediate temperature. We use that expression to show that for temperatures large compared to the mean level spacing of the system, the heat conductance is inversely proportional to the level density and, thus, inversely proportional to the length of the system.

  9. Quasi-one-dimensional scattering in a discrete model

    Energy Technology Data Exchange (ETDEWEB)

    Valiente, Manuel; Moelmer, Klaus [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

    2011-11-15

    We study quasi-one-dimensional scattering of one and two particles with short-range interactions on a discrete lattice model in two dimensions. One of the directions is tightly confined by an arbitrary trapping potential. We obtain the collisional properties of these systems both at finite and zero Bloch quasimomenta, considering as well finite sizes and transversal traps that support a continuum of states. This is made straightforward by using the exact ansatz for the quasi-one-dimensional states from the beginning. In the more interesting case of genuine two-particle scattering, we find that more than one confinement-induced resonances appear due to the nonseparability of the center-of-mass and relative coordinates on the lattice. This is done by solving its corresponding Lippmann-Schwinger-like equation. We characterize the effective one-dimensional interaction and compare it with a model that includes only the effect of the dominant, broadest resonance, which amounts to a single-pole approximation for the interaction coupling constant.

  10. Characterizing high- n quasi-one-dimensional strontium Rydberg atoms

    Science.gov (United States)

    Hiller, Moritz; Yoshida, Shuhei; Burgdörfer, Joachim; Ye, Shuzhen; Zhang, Xinyue; Dunning, F. Barry

    2014-05-01

    The production of high- n, n ~ 300 , quasi-one-dimensional strontium Rydberg atoms by two-photon excitation of selected extreme Stark states in the presence of a weak dc field is examined using a crossed laser-atom beam geometry. The polarization of the product states is probed using three independent techniques which are analyzed with the aid of classical-trajectory Monte Carlo simulations that employ initial ensembles based on quantum calculations using a two-active-electron model. Comparisons between theory and experiment demonstrate that the product states have large dipole moments, ~ 1 . 0 - 1 . 2n2 a . u . and that they can be engineered using pulsed electric fields to create a wide variety of target states. Research supported by the NSF, the Robert A Welch Foundation, and the FWF (Austria).

  11. Correlation effects for a quasi-one-dimensional polaron gas

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Paulo Cesar Miranda [Escola de Engenharia Eletrica e de Computacao, Universidade Federal de Goias, Goiania (Brazil); Borges, Antonio Newton; Osorio, Francisco Aparecido Pinto [Instituto de Fisica, Universidade Federal de Goias, Goiania (Brazil); Nucleo de Pesquisa em Fisica, Pontificia Universidade Catolica de Goias, Goiania (Brazil)

    2011-04-15

    In this work, we investigate the plasmon-LO phonon interaction effects on the intrasubband structure factor, electron-electron effective potential, and plasmon energy associated with the lowest subband in a GaAs-AlGaAs rectangular quantum-well wire (QWW) as a function of the electronic density. Our calculations are performed using the self-consistent field approximation, which includes the local-field correction (LFC) within the Singwi, Tosi, Land, and Sjolander (STLS) theory, at zero temperature and assuming a three-subband model, where only the first subband is occupied by electrons. We report for the first time dips in the structure factor spectra as a function of the quasi-one-dimensional (Q1D) plasmon-LO phonon wavevector that are directly related with the resonant split of the collective excitation energy into two branches due to the polaronic effects. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Organic Conductors

    DEFF Research Database (Denmark)

    Andersen, Jan Rud; Jacobsen, Claus S.; Rindorf, Grethe;

    1975-01-01

    2,3,6,7-Tetramethyl-1,4,5,8-tetraselenafulvalene reacts with 2,5-dimethyl-7,7′,8,8′-tetracyano-p-quinodi-methane to give a highly conducting organic solid.......2,3,6,7-Tetramethyl-1,4,5,8-tetraselenafulvalene reacts with 2,5-dimethyl-7,7′,8,8′-tetracyano-p-quinodi-methane to give a highly conducting organic solid....

  13. Neutron and photon (light) scattering on solitons in the quasi-one-dimensional magnetics

    CERN Document Server

    Abdulloev, K O

    1999-01-01

    The general expression we have found earlier for the dynamics form-factor is used to analyse experiments on the neutron and photon (light) scattering by the gas of solitons in quasi-one-dimensional magnetics (Authors)

  14. Prediction of inorganic superconductors with quasi-one-dimensional crystal structure

    OpenAIRE

    Volkova, L. M.; Marinin, D. V.

    2012-01-01

    Models of superconductors having a quasi-one-dimensional crystal structure based on the convoluted into a tube Ginzburg sandwich, which comprises a layered dielectric-metal-dielectric structure, have been suggested. The critical crystal chemistry parameters of the Ginzburg sandwich determining the possibility of the emergence of superconductivity and the Tc value in layered high-Tc cuprates, which could have the same functions in quasi-one-dimensional fragments (sandwich-type tubes), have bee...

  15. Focus on Organic Conductors

    Directory of Open Access Journals (Sweden)

    Shinya Uji, Takehiko Mori and Toshihiro Takahashi

    2009-01-01

    Full Text Available Organic materials are usually thought of as electrical insulators. Progress in chemical synthesis, however, has brought us a rich variety of conducting organic materials, which can be classified into conducting polymers and molecular crystals. Researchers can realize highly conducting molecular crystals in charge-transfer complexes, where suitable combinations of organic electron donor or acceptor molecules with counter ions or other organic molecules provide charge carriers. By means of a kind of chemical doping, the charge-transfer complexes exhibit high electrical conductivity and, thanks to their highly crystalline nature, even superconductivity has been observed. This focus issue of Science and Technology of Advanced Materials is devoted to the research into such 'organic conductors'The first organic metal was (TTF(TCNQ, which was found in 1973 to have high conductivity at room temperature and a metal–insulator transition at low temperatures. The first organic superconductor was (TMTSF2PF6, whose superconductivity under high pressures was reported by J´erome in 1980. After these findings, the research on organic conductors exploded. Hundreds of organic conductors have been reported, among which more than one hundred exhibit superconductivity. Recently, a single-component organic conductor has been found with metallic conductivity down to low temperatures.In these organic conductors, in spite of their simple electronic structures, much new physics has arisen from the low dimensionality. Examples are charge and spin density waves, characteristic metal–insulator transitions, charge order, unconventional superconductivity, superconductor–insulator transitions, and zero-gap conductors with Dirac cones. The discovery of this new physics is undoubtedly derived from the development of many intriguing novel organic conductors. High quality single crystals are indispensable to the precise measurement of electronic states.This focus issue

  16. Synthesis and engineering of quasi-one dimensional nano-materials

    Science.gov (United States)

    Chang, Pai-Chun

    Quasi-one-dimensional (Q1D) nanoscale systems have been intensively investigated and proven to be of great potential as nanoelectronics building blocks. Nanowires made from organic, inorganic are now available and give research opportunities for understanding of nanomaterials and future applications. In this field, the research can be divided into three categories: nanomaterial synthesis, material characterizations, device fabrication for applications. These three main thrusts govern the research route to understand the Q1D systems. This dissertation also follows these three basic elements and consists of eight chapters. Chapter 1 will give an introduction of low dimensional systems. Chapter 2 and 3 will discuss how nanowires be synthesized in vapor phase. Chapter 4 and 5 will investigate the liquid phase growth. In Chapter 6, unique properties of nanowires due to the shrinkage in size will be depicted. Chapter 7 demonstrates a process to implement high performance nanowire field effect transistors, which are the basic element in nanoelectronics devices. In the last chapter, few possible future directions of nanoelectronic applications will be given and discussed.

  17. Quasi-one-dimensional photonic crystal as a compact building block for refractometric optical sensors

    NARCIS (Netherlands)

    Hopman, Wico C.L.; Pottier, Pierre; Yudistira, Didit; Lith, van Joris; Lambeck, Paul V.; De La Rue, Richard M.; Driessen, Alfred; Hoekstra, Hugo J.W.M.; Ridder, de René M.

    2005-01-01

    We report the fabrication and the characterization of the refractometric and thermo-optical properties of a quasi-one-dimensional waveguide photonic crystal-a strong, 76-micron-long Bragg grating. The transmission spectra (around 660 nm) of the structure have been measured as a function of both the

  18. Quasi One-Dimensional Photonic Crystals as Building Block for Compact Integrated Optical Refractometric Sensors

    NARCIS (Netherlands)

    Hopman, Wico; Pottier, Pierre; Yudistira, Didit; Lith, van Joris; Lambeck, Paul; De La Rue, Richard; Driessen, Alfred; Hoekstra, Hugo J.W.M.; Ridder, de René M.

    2004-01-01

    A quasi one-dimensional photonic crystal has been fabricated and the applicability of this strong grating for optical sensing has been investigated by measuring the transmission spectra as a function of the cladding refractive index. The cladding index was varied a small range. By monitoring the tra

  19. Stereoscopic study of the angle-dependent magnetoresistance oscillations across the charge-density-wave transition of the organic conductor α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Kang, W.; Osada, T.; Konoike, T.; Uchida, K.

    2013-11-01

    The stereoscopic angle-dependent magnetoresistance oscillations (AMRO) in an organic conductor α-(BEDT-TTF)2KHg(SCN)4 were measured across the temperature-pressure boundary that separates the charge-density-wave state from the metallic state. The gnomonic projections of the data clearly resolved the contributions from different parts of the Fermi surfaces. The temperature and pressure dependencies of the AMRO results revealed the progressive formation of a quasi-one-dimensional orbit in the charge-density-wave state. The AMRO measurements at ambient pressures and at low temperatures revealed the presence of two sets of quasi-one-dimensional Fermi surfaces. Additional evidence for multiple quasi-one-dimensional orbits was obtained from the data collected in conjunction with the in-plane field rotations.

  20. The kink-soliton and antikink-soliton in quasi-one-dimensional nonlinear monoatomic lattice

    Institute of Scientific and Technical Information of China (English)

    XU; Quan; TIAN; Qiang

    2005-01-01

    The quasi-one-dimensional nonlinear monoatomic lattice is analyzed. The kink-soliton and antikink-soliton are presented. When the interaction of the lattice is strong in the x-direction and weak in the y-direction, the two-dimensional (2D) lattice changes to a quasi-one-dimensional lattice. Taking nearest-neighbor interaction into account, the vibration equation can be transformed into the KPI, KPII and MKP equation. Considering the cubic nonlinear potential of the vibration in the lattice, the kink-soliton solution is presented. Considering the quartic nonlinear potential and the cubic interaction potential, the kink-soliton and antikink-soliton solutions are presented.

  1. Twisting phonons in complex crystals with quasi-one-dimensional substructures.

    Science.gov (United States)

    Chen, Xi; Weathers, Annie; Carrete, Jesús; Mukhopadhyay, Saikat; Delaire, Olivier; Stewart, Derek A; Mingo, Natalio; Girard, Steven N; Ma, Jie; Abernathy, Douglas L; Yan, Jiaqiang; Sheshka, Raman; Sellan, Daniel P; Meng, Fei; Jin, Song; Zhou, Jianshi; Shi, Li

    2015-04-15

    A variety of crystals contain quasi-one-dimensional substructures, which yield distinctive electronic, spintronic, optical and thermoelectric properties. There is a lack of understanding of the lattice dynamics that influences the properties of such complex crystals. Here we employ inelastic neutron scatting measurements and density functional theory calculations to show that numerous low-energy optical vibrational modes exist in higher manganese silicides, an example of such crystals. These optical modes, including unusually low-frequency twisting motions of the Si ladders inside the Mn chimneys, provide a large phase space for scattering acoustic phonons. A hybrid phonon and diffuson model is proposed to explain the low and anisotropic thermal conductivity of higher manganese silicides and to evaluate nanostructuring as an approach to further suppress the thermal conductivity and enhance the thermoelectric energy conversion efficiency. This discovery offers new insights into the structure-property relationships of a broad class of materials with quasi-one-dimensional substructures for various applications.

  2. Electrical instability in quasi-one-dimensional charge density wave conductors

    Science.gov (United States)

    Sukumar, B.; Navaneethakrishnan, K.

    1985-01-01

    The results obtained for the strain energy corrections to O and Se donor ionization energies in GaP (at the P site) by Van Cong et al. in a recent communication [1] are shown to be fortuitous. It is pointed out that the results of Weinreich [2] are of the correct order unlike the results of Van Cong et al. which are too high in many cases and are not in agreement with experiment.

  3. Photoconduction spectra of quasi-one-dimensional conductor NbS{sub 3}(I)

    Energy Technology Data Exchange (ETDEWEB)

    Nasretdinova, V., E-mail: venera@cplire.ru [Kotelnikov IRE RAS, Mokhovaya 11, bld.7, 125009 Moscow (Russian Federation); Zaitsev-Zotov, S. [Kotelnikov IRE RAS, Mokhovaya 11, bld.7, 125009 Moscow (Russian Federation)

    2012-06-01

    Photoconduction spectra as a function of temperature, electric field and additional illumination are studied in crystals of NbS{sub 3} (phase I). We observe the low-energy cut-off of photoconduction corresponding to the gap edge and electronic states within the gap. The states reveal themselves as peaks in photoconduction spectra; the amplitude of the peaks depends on the value of electric field applied, temperature and additional illumination. Two peaks at energies 0.6 eV and 0.9 eV and a tail of photoconduction at energies between 1 eV and 0.7 eV are observed. In addition, the effect of plastic deformation created by bending of a sample on the photoconduction spectra is studied. We found that plastic deformation of the sample results in suppression of the peak at Planck-Constant-Over-Two-Pi {omega}=0.6eV.

  4. Spectral properties of quasi-one-dimensional conductors with a finite transverse band dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Losic, Z Bonacic; Zupanovic, P [Department of Physics, Faculty of Natural Sciences, Mathematics and Kinesiology, University of Split, Teslina 12, 21000 Split (Croatia); Bjelis, A [Department of Physics, Faculty of Science, University of Zagreb, POB 162, 10001 Zagreb (Croatia)], E-mail: agicz@pmfst.hr, E-mail: bjelis@phy.hr

    2008-08-13

    We determine the one-particle spectral function and the corresponding derived quantities for the conducting chain lattice with finite inter-chain hopping t{sub perpendicular} and three-dimensional long-range Coulomb electron-electron interaction. The standard G{sub 0}W{sub 0} approximation is used. It is shown that, due to the optical character of the anisotropic plasmon dispersion caused by the finite t{sub perpendicular}, a low energy quasi-particle {delta}-peak appears in the spectral function in addition to the hump present at energies of the order of the plasmon energy. Particular attention is devoted to the continuous crossover from the non-Fermi liquid regime to the Fermi liquid regime with increasing t{sub perpendicular}. It is shown that the spectral weight of the hump transfers to the quasi-particle as the optical gap in the plasmon dispersion increases together with t{sub perpendicular}, with the quasi-particle residuum Z behaving like -ln t{sub perpendicular}){sup -1} in the limit t{sub perpendicular} {yields}0. Our approach is appropriate for the wide range of energy scales given by the plasmon energy and the width of the conduction band, and is complementary to the Luttinger liquid techniques that are limited to the low energy regime close to the Fermi surface.

  5. Quantum-chemical studies of quasi-one-dimensional electron systems. 1. Polyenes

    Directory of Open Access Journals (Sweden)

    Yuriy Kruglyak

    2015-05-01

    Full Text Available This review is devoted to the basic problem in quantum theory of quasi-one-dimensional electron systems like polyenes (Part 1 and cumulenes (Part 2 – physical origin of the forbidden zone in these and analogous 1D electron systems due to two possible effects – Peierls instability (bond alternation and Mott instability (electron correlation. Both possible contradiction and coexistence of the Mott and Peierls instabilities are summerized on the basis of the Kiev quantum chemistry team research projects.

  6. Localized Mode Enhanced Coupler Based on Quasi-One-Dimensional Photonic Crystal Microstrip

    Institute of Scientific and Technical Information of China (English)

    LI Yun-Hui; JIANG Hai-Tao; HE Li; LI Hong-Qiang; ZHANG Ye-Wen; CHEN Hong

    2004-01-01

    We propose a novel localized mode enhanced (LME) coupler based on quasi-one-dimensional photonic crystal microstrips, which is promising to be applied in wavelength division multiplexed microwave communication systems. Compared to the traditional microstrip coupler, the LME structure has two advantages: high efficiency and frequency selectivity. Even in a relatively far coupling distance, this structure can still achieve a high efficiency about 50%. The frequency selectivity can be realized by simply tuning the distance between two transmission lines.

  7. Observation of localized flat-band modes in a quasi-one-dimensional photonic rhombic lattice.

    Science.gov (United States)

    Mukherjee, Sebabrata; Thomson, Robert R

    2015-12-01

    We experimentally demonstrate the photonic realization of a dispersionless flat band in a quasi-one-dimensional photonic lattice fabricated by ultrafast laser inscription. In the nearest neighbor tight binding approximation, the lattice supports two dispersive and one nondispersive (flat) band. We experimentally excite superpositions of flat-band eigenmodes at the input of the photonic lattice and show the diffractionless propagation of the input states due to their infinite effective mass. In the future, the use of photonic rhombic lattices, together with the successful implementation of a synthetic gauge field, will enable the observation of Aharonov-Bohm photonic caging.

  8. A Quasi-One-Dimensional Model for a Solar Flux Tube

    Institute of Scientific and Technical Information of China (English)

    杨志良; 张洪起; 张枚; 冯学尚

    2002-01-01

    We develop the quasi-one-dimensional flux tube model with magnetohydrodynamical equations. In order to know whether the magnetic field can maintain their similar structurefrom photosphere to chromosphere, we suppose that the flux tube is thin in radius relative to the length, and that the quantities in the cross section are averaged.The radii of the flux tube and the magnetic field are numerically simulated. One of the important results shows that the flux tube does not expand as quickly as the existing model when it is out of the photosphere with high velocity. This is consistent with observations of the magnetic field in the photosphere and chromosphere.

  9. The effect of magnetic frustrations in a structure of Quasi-One-Dimensional Heisenberg antiferromagnetic chain

    Energy Technology Data Exchange (ETDEWEB)

    Cui, L.; Wang, F. [Suqian College, Fundamental Department, Suqian 223800 (China); Zhang, S.J. [Hubei University of Automotive Technology, Shiyan 442002 (China); Hu, Y.J., E-mail: eric8222@126.com [Hubei University of Automotive Technology, Shiyan 442002 (China)

    2014-10-15

    Using exact numerical diagonalization and density-matrix renormalization group method, we study the effect of magnetic frustrations due to next-nearest-neighbor bonds in a structure of periodically doping spins beside every spin side of the same sublattice of the 1D HAF linear chain, which is popularly known as Quasi-One-Dimensional Heisenberg Antiferromagnetic chain. As a result of the frustrations, the quantum disordered phase (gapped) also appears in the quantum case, except that the ferrimagnetic state in the non-frustrations case and the caned phase appeared in the classical case. For quantum disordered phase, tetramer–dimmer state is predominant and the spin gap is opened.

  10. Quasi-One-Dimensional Electronic States Inside and Outside Helium-Plated Carbon Nanotubes

    Science.gov (United States)

    Motta, M.; Galli, D. E.; Liebrecht, M.; Del Maestro, A.; Cole, M. W.

    2016-10-01

    About one-half a century ago, it was realized that electrons experience a repulsive barrier when approaching the surface of condensed phases of helium, hydrogen, and neon. This led to the proposal and subsequent observation of image-potential surface-bound electronic states, which exhibit intriguing quasi-two-dimensional behavior. In the present work, we report similar quasi-one-dimensional electronic states by exploring single-wall carbon nanotubes coated both inside and outside by thin helium films. Electrons near such structures are localized in the radial direction, but free to move along the nanotube axis. The many-body aspects of the system are discussed qualitatively.

  11. Fourier's law for quasi-one-dimensional chaotic quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Seligman, Thomas H [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, C.P. 62210 Cuernavaca, Morelos (Mexico); Weidenmueller, Hans A, E-mail: Hans.Weidenmueller@mpi-hd.mpg.de [Max-Planck-Institut fuer Kernphysik, PO Box 103980, 69029 Heidelberg (Germany)

    2011-05-20

    We derive Fourier's law for a completely coherent quasi-one-dimensional chaotic quantum system coupled locally to two heat baths at different temperatures. We solve the master equation to first order in the temperature difference. We show that the heat conductance can be expressed as a thermodynamic equilibrium coefficient taken at some intermediate temperature. We use that expression to show that for temperatures large compared to the mean level spacing of the system, the heat conductance is inversely proportional to the level density and, thus, inversely proportional to the length of the system.

  12. Alloy-disorder scattering in the quasi-one dimensional electron gas

    Science.gov (United States)

    Gold, A.; Ghazali, A.

    1992-08-01

    We calculate the mobility μ due to alloy-disorder scattering in a quasi-one-dimensional electron gas. In the one-subband approximation the screening effects are taken into account. We discuss the dependence of μ on the wire radius and the electron density and derive analytical results. We compare our results with the mobility due to interface-roughness scattering and conclude that in In 0.53Ga 0.47As/InP wires alloy-disorder scattering is more important than interface-roughness scattering. Our results should apply to recently realized In 0.53Ga 0.47As/InP wires.

  13. Thermal Growth and Nanomagnetism of the Quasi-one Dimensional Iron Oxide

    Institute of Scientific and Technical Information of China (English)

    Minglong Zhong; Zhongwu Liu; Xichun Zhong; Hongya Yu; Dechang Zeng

    2011-01-01

    Quasi-one dimensional iron oxide nanowires with flat needle shape were synthesized on the iron powders by a rather simple catalyst-free thermal oxidation process in ambient atmosphere. The characterization by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman and high-resolution transmission electron microscopy (HRTEM) revealed that these nanos- tructures are single crystalline α-Fe2O3. The various dimensions with 40-170 nm in width and 1-8 μm in length were obtained by tuning the growth temperature from 280 to 480℃. A surface diffusion mechanism was proposed to account for the growth of quasi-one dimensional nanostructure. The typical α-Fe203 nanowires synthesized at 430℃ had a reduced Morin temperature TM of 131 K in comparison with their bulk counterpart. The coercivitis Hc of these nanowires are 321 and 65 Oe at 5 and 300 K, respectively. The temperature of synthesis also has important effects on the magnetic properties of these nanowires.

  14. Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect.

    Science.gov (United States)

    Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

    2016-02-29

    Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb(3+)/Er(3+) microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser.

  15. Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect

    Science.gov (United States)

    Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

    2016-02-01

    Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb3+/Er3+ microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser.

  16. Variability and self-average of impurity-limited resistance in quasi-one dimensional nanowires

    Science.gov (United States)

    Sano, Nobuyuki

    2017-02-01

    The impurity-limited resistance in quasi-one dimensional (quasi-1D) nanowires is studied under the framework of the Lippmann-Schwinger scattering theory. The resistance of cylindrical nanowires is calculated theoretically under various spatial configurations of localized impurities with a simplified short-range scattering potential. Then, the relationship between the phase interference and the variability in the impurity-limited resistances is clarified. We show that there are two different and independent mechanisms leading to the variability in impurity-limited resistances; incoherent and phase-coherent randomization processes. The latter is closely related to the so-called "self-average" and its physical origin under nanowire structures is clarified. We point out that the ensemble average also comes into play in the cases of long channel nanowires, which leads to the self-average resistance of multiple impurities.

  17. Nonlinear electrodynamics of electrons in a quasi-one-dimensional ballistic ring

    Energy Technology Data Exchange (ETDEWEB)

    Epshtein, E.M. [Institute for Radioengineering and Electronics, Russian Academy of Sciences, Moscow (Russian Federation); Shmelev, G.M.; Maglevanny, I.I. [Volgograd State Pedagogical University, Volgograd (Russian Federation)

    2000-09-01

    We consider ballistic electron motion in a quasi-one-dimensional ring under the uniform high-frequency electric field induced by an electromagnetic field. The electron satisfies a nonlinear equation of motion which is formally identical to that for a pendulum with a vibrating suspension point. The averaging method of Kapitza is used. The electromagnetic emission spectrum is calculated. The spectrum consists of low-frequency radiation, scattered radiation at the incident radiation frequency and combination scattered radiation; the intensities and frequencies of all components depend nonlinearly on the incident radiation frequency. At a certain value of that intensity the spontaneous symmetry breakdown occurs. As a result, the system acquires some static electric dipole moment. (author)

  18. Nonlinear electrodynamics of electrons in a quasi-one-dimensional ballistic ring

    Science.gov (United States)

    Epshtein, E. M.; Shmelev, G. M.; Maglevanny, I. I.

    2000-09-01

    We consider ballistic electron motion in a quasi-one-dimensional ring under the uniform high-frequency electric field induced by an electromagnetic field. The electron satisfies a nonlinear equation of motion which is formally identical to that for a pendulum with a vibrating suspension point. The averaging method of Kapitza is used. The electromagnetic emission spectrum is calculated. The spectrum consists of low-frequency radiation, scattered radiation at the incident radiation frequency and combination scattered radiation; the intensities and frequencies of all components depend nonlinearly on the incident radiation frequency. At a certain value of that intensity the spontaneous symmetry breakdown occurs. As a result, the system acquires some static electric dipole moment.

  19. Quasi-one-dimensional spin-orbit-coupled correlated insulator in a multinuclear coordinated organometallic crystal

    Science.gov (United States)

    Merino, J.; Jacko, A. C.; Khosla, A. L.; Powell, B. J.

    2016-11-01

    We show how quasi-one-dimensional correlated insulating states arise at two-thirds filling in organometallic multinuclear coordination complexes described by layered decorated honeycomb lattices. The interplay of spin-orbit coupling and electronic correlations leads to pseudospin-one moments arranged in weakly coupled chains with highly anisotropic exchange and a large trigonal splitting. We show that the in-plane exchange coupling is very different from the interlayer coupling; in particular the latter is much larger, despite the underlying hopping integrals being close to isotropic. Surprisingly, the effective dimensionality of the pseudospin model is strongly dependent on the strength of the electronic correlations: With increasing Hubbard U the pseudospin-one model becomes increasingly one dimensional, even though the crystal is almost isotropic. We predict that the trigonal splitting leads to a quantum phase transition from a Haldane phase to a topologically trivial phase as the relative strength of the spin-orbit coupling increases.

  20. Subharmonic wave transition in a quasi-one-dimensional noisy fluidized shallow granular bed.

    Science.gov (United States)

    Ortega, Ignacio; Clerc, Marcel G; Falcón, Claudio; Mujica, Nicolás

    2010-04-01

    We present an experimental and theoretical study of the pattern formation process of standing subharmonic waves in a fluidized quasi-one-dimensional shallow granular bed. The fluidization process is driven by means of a time-periodic air flow, analogous to a tapping type of forcing. Measurements of the amplitude of the critical mode close to the transition are in quite good agreement with those inferred from a universal stochastic amplitude equation. This allows us to determine both the bifurcation point of the deterministic system and the corresponding noise intensity. We also show that the probability density distribution is well described by a generalized Rayleigh distribution, which is the stationary solution of the corresponding Fokker-Planck equation of the universal stochastic amplitude equation that describes our system.

  1. Shapiro spikes and negative mobility for skyrmion motion on quasi-one-dimensional periodic substrates

    Science.gov (United States)

    Reichhardt, C.; Reichhardt, C. J. Olson

    2017-01-01

    Using a simple numerical model of skyrmions in a two-dimensional system interacting with a quasi-one-dimensional periodic substrate under combined dc and ac drives where the dc drive is applied perpendicular to the substrate periodicity, we show that a rich variety of novel phase-locking dynamics can occur due to the influence of the Magnus term on the skyrmion dynamics. Instead of Shapiro steps, the velocity response in the direction of the dc drive exhibits a series of spikes, including extended dc drive intervals over which the skyrmions move in the direction opposite to the dc drive, producing negative mobility. There are also specific dc drive values at which the skyrmions move exactly perpendicular to the dc drive direction, giving a condition of absolute transverse mobility.

  2. Direct three-dimensional ordering of quasi-one-dimensional quantum dimer system near critical fields

    Science.gov (United States)

    Matsushita, Taku; Hori, Nobuyoshi; Takata, Seiya; Wada, Nobuo; Amaya, Naoki; Hosokoshi, Yuko

    2017-01-01

    Dimensionalities of X X Z spin orderings or degenerate hard-core bosons in a quasi-one-dimensional (1D) dimer system are examined by the ac susceptibility and specific heat of antiferromagnetic bond-alternating chains in pentafluorophenyl nitronyl nitroxide (F5PNN ). At intermediate fields in the gapless region, the 1D short-range order (SRO) corresponding to the Tomonaga-Luttinger liquid and three-dimensional (3D) long-range order (LRO BEC) at lower temperatures are separately observed, as expected from the small interchain interaction. In contrast, a definite region around the critical field was established where 3D LRO occurs without the development of 1D SRO at higher temperatures.

  3. Self-consistent GW for a quasi-one-dimensional semiconductor

    Science.gov (United States)

    de Groot, H. J.; Bobbert, P. A.; van Haeringen, W.

    1995-10-01

    We present self-consistent GW calculations for a quasi-one-dimensional model semiconductor, using multipole representations for W, the screened interaction, and G, the electron Green function. In the case of G, we distinguish between the quasiparticle contribution and the so-called incoherent contribution. We consider various strengths of the external potential. For two different starting points of the self-consistency cycle, local-density approximation and Hartree-Fock, the band gaps converge to the same values. The self-consistent GW band gaps differ very little from the Hartree-Fock band gaps. There is considerable disagreement with quantum Monte Carlo calculations for the same model, indicating the importance of vertex corrections.

  4. Angle-resolved photoemission study of quasi one-dimensional TlInSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, Kojiro [Department of Mathematical Sciences, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan)], E-mail: mimura@ms.osakafu-u.ac.jp; Wakita, Kazuki [Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan); Arita, Masashi [Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046 (Japan); Mamedov, Nazim; Orudzhev, Guseyn [Institute of Physics, Azerbaijan National Academy of Science, Baku, AZ-1143 (Azerbaijan); Taguchi, Yukihiro; Ichikawa, Kouichi [Department of Mathematical Sciences, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan); Namatame, Hirofumi; Taniguchi, Masaki [Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046 (Japan)

    2007-05-15

    TlInSe{sub 2} with a quasi one-dimensional chain structure and a giant Seebeck coefficient of more than 10{sup 6} {mu}V/K below 140 {sup o}C has been investigated by means of angle-resolved photoemission spectroscopy at 50 K and 280 K. The obtained energy bands favorably agree with the calculated band structure and show quite noticeable dispersion in the direction normal to the chains. A rigid shift toward lower binding energies, a splitting and the formation of the mini-gap-like structures are clearly observed in the experimental electronic bands with the temperature reduced to 50 K. These features are indicative of an incommensurate superlattice phase emerging in TlInSe{sub 2} with temperature, and causing the record-breaking values of Seebeck coefficient.

  5. Quasi-one dimensional (Q1D) nanostructures: Synthesis, integration and device application

    Science.gov (United States)

    Chien, Chung-Jen

    Quasi-one-dimensional (Q1D) nanostructures such as nanotubes and nanowires have been widely regarded as the potential building blocks for nanoscale electronic, optoelectronic and sensing devices. In this work, the content can be divided into three categories: Nano-material synthesis and characterizations, alignment and integration, physical properties and application. The dissertation consists of seven chapters as following. Chapter 1 will give an introduction to low dimensional nano-materials. Chapter 2 explains the mechanism how Q1D nanostructure grows. Chapter 3 describes the methods how we horizontally and vertically align the Q1D nanostructure. Chapter 4 and 5 are the electrical and optical device characterization respectively. Chapter 6 demonstrates the integration of Q1D nanostructures and the device application. The last chapter will discuss the future work and conclusion of the thesis.

  6. Quantum Fluctuations in Quasi-One-Dimensional Dipolar Bose-Einstein Condensates

    Science.gov (United States)

    Edler, D.; Mishra, C.; Wächtler, F.; Nath, R.; Sinha, S.; Santos, L.

    2017-08-01

    Recent experiments have revealed that beyond-mean-field corrections are much more relevant in weakly interacting dipolar condensates than in their nondipolar counterparts. We show that in quasi-one-dimensional geometries quantum corrections in dipolar and nondipolar condensates are strikingly different due to the peculiar momentum dependence of the dipolar interactions. The energy correction of the condensate presents not only a modified density dependence, but it may even change from attractive to repulsive at a critical density due to the surprising role played by the transversal directions. The anomalous quantum correction translates into a strongly modified physics for quantum-stabilized droplets and dipolar solitons. Moreover, and for similar reasons, quantum corrections of three-body correlations, and hence of three-body losses, are strongly modified by the dipolar interactions. This intriguing physics can be readily probed in current experiments with magnetic atoms.

  7. Bi(114): A quasi one-dimensional metal with strong spin-orbit splitting

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Philip; Rienks, Emile; Fuglsang Jensen, Maria [University of Aarhus (Denmark); Wells, Justin [University of Aarhus (Denmark); University of Science and Technology, Trondheim (Norway); Dil, Hugo; Meier, Fabian; Lobo-Checa, Jorge [Universitaet Zuerich-Irchel (Switzerland); Paul Scherrer Institut (Switzerland); Petrov, Vladimir [St. Petersburg Technical University (Russian Federation); Osterwalder, Juerg [Universitaet Zuerich-Irchel (Switzerland); Ugeda, Miguel Moreno; Fernandez-Torrente, Isabel; Pascual, Jose Ignacio [Freie Universitaet Berlin (Germany)

    2009-07-01

    The (114) vicinal surface of the semimetal Bi is found to support a quasi one-dimensional, metallic surface state. As required by symmetry, the state is degenerate along the anti {gamma}- anti Y line of the surface Brillouin zone with a highest binding energy of {approx}100 meV. In the anti {gamma}- anti X direction the degeneracy is lifted by the strong spin-orbit interaction, as directly shown by spin-resolved photoemission. This results in a Fermi surface consisting of two closely separated, parallel lines of opposite spin direction. We discuss these findings in the light of the recently discovered topological stability of surface states on BiSb topological insulators.

  8. Magneto-optical studies of low-dimensional organic conductors

    Directory of Open Access Journals (Sweden)

    Hitoshi Ohta, Motoi Kimata and Yugo Oshima

    2009-01-01

    Full Text Available Our periodic orbit resonance (POR results on quasi-two-dimensional (q2D, highly anisotropic q2D and quasi-one-dimensional (q1D organic conductors are reviewed together with our rotational cavity magneto-optical measurement system. Higher order POR up to seventh order has been observed in the q2D system (BEDT-TTF2Br(DIA, and the experimental conditions to observe POR and the cyclotron resonance (CR are discussed. Highly anisotropic q2D Fermi surface (FS in β''-(BEDT-TTF(TCNQ, which was considered to have q1D FS previously, is proposed by our POR measurements, and the possible interpretations of other experimental results of β''-(BEDT-TTF(TCNQ are discussed assuming the highly anisotropic q2D FS. Finally, detailed q1D FS of (DMET2I3, obtained from our POR results, is discussed in connection with the typical q1D system (TMTSF2ClO4.

  9. Conductive Mechanism of Organic Conductor

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Organic conductor is a kind of organic compound which has special electronic and magnetic properties. The research of the organic compounds has received considerable attention because of their potential applications in many areas. The molecular conductive units are theoretically investigated as well as their energy gap and charge distribution. The relationship of conductivity and micro-mechanism is discussed.

  10. Ultrafast optical spectroscopy of quasi one dimensional Ta{sub 2}NiSe{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Mor, Selene; Herzog, Marc; Monney, Claude; Staehler, Julia; Wolf, Martin [Fritz-Haber-Institut der MPG, Dept. of Phys. Chem., Berlin (Germany)

    2015-07-01

    Ta2NiSe5 is a layered compound in which atomic chains are aligned in the layers, forming a quasi one dimensional crystal structure. At 328 K, the system shows a structural change, which is accompanied by an electronic phase transition from a semiconductor to an excitonic insulator, with an estimated energy gap of about few hundreds millielectronvolts. Our aim is to unveil the microscopic mechanisms underlying the phase transition in Ta{sub 2}NiSe{sub 5}. The system is excited with a femtosecond Ti:sapphire fundamental laser pulse and the mid-infrared (MIR) transient optical response is monitored by ultrafast optical spectroscopy. We observe a fast rise of transient reflectivity, which decays exponentially. This incoherent response is superimposed by a coherent phonon oscillation. A preliminary study with white light (WL) probe beam shows that low repetition rate is mandatory to study the response of the photoexcited system. The analysis unveils the presence of two phonons at 3 and 4 THz, that dominate at high (HT) and low (LT) temperature, respectively. We study the time evolution of the two phonons in the LT phase. We reveal a finite lifetime for the LT phase phonon, whose amplitude decays within few picoseconds, while the HT phase phonon amplitude remains almost constant. The picture is supported by temperature-dependent Raman spectroscopy.

  11. Giant exciton Fano resonance in quasi-one-dimensional Ta2NiSe5

    Science.gov (United States)

    Larkin, T. I.; Yaresko, A. N.; Pröpper, D.; Kikoin, K. A.; Lu, Y. F.; Takayama, T.; Mathis, Y.-L.; Rost, A. W.; Takagi, H.; Keimer, B.; Boris, A. V.

    2017-05-01

    We report the complex dielectric function of the quasi-one-dimensional chalcogenide Ta2NiSe5 , which undergoes a structural phase transition presumably associated with exciton condensation below Tc=326 K [Y. Wakisaka et al., Phys. Rev. Lett. 103, 026402 (2009), 10.1103/PhysRevLett.103.026402; Y. F. Lu et al., Nat. Commun. 8, 14408 (2017), 10.1038/ncomms14408], and of the isostructural Ta2NiS5 , which does not exhibit such a transition. Using spectroscopic ellipsometry, we have detected exciton doublets with pronounced Fano line shapes in both the compounds. The exciton Fano resonances in Ta2NiSe5 display an order-of-magnitude higher intensity than those in Ta2NiS5 . In conjunction with prior theoretical work [E. Rashba, Sov. Phys. Semicond. 8, 807 (1975)], we attribute this observation to the giant oscillator strength of spatially extended exciton-phonon bound states in Ta2NiSe5 . The formation of exciton-phonon complexes in Ta2NiS5 and Ta2NiSe5 is confirmed by the pronounced temperature dependence of sharp interband transitions in the optical spectra, the peak energies and widths of which scale with the thermal population of optical phonon modes. The description of the optically excited states in terms of strongly overlapping exciton complexes is in good agreement with the hypothesis of an exciton insulator ground state.

  12. Unconventional Andreev reflection on the quasi-one-dimensional superconductor Nb2PdxSe5

    Directory of Open Access Journals (Sweden)

    Yeping Jiang

    2016-04-01

    Full Text Available We have carried out Andreev reflection measurements on point contact junctions between normal metal and single crystals of the quasi-one-dimensional (Q1D superconductor Nb2PdxSe5 (Tc ∼ 5.5 K. The contacts of the junctions were made on either self-cleaved surfaces or crystal edges so that the current flow directions in the two types of junctions are different, and the measurements provide a directional probe for the order parameter of the superconductor. Junctions made in both configurations show typical resistances of ∼20-30 Ohms, and a clear double-gap Andreev reflection feature was consistently observed at low temperatures. Quantitative analysis of the conductance spectrum based on a modified Blonder-Tinkham-Klapwijk (BTK model suggests that the amplitudes of two order parameters may have angular dependence in the a-c plane. Moreover, the gap to transition temperature ratio (Δ/TC for the larger gap is substantially higher than the BCS ratio expected for phonon-mediated s-wave superconductors. We argue that the anisotropic superconducting order parameter and the extremely large gap to transition temperature ratio may be associated with an unconventional pairing mechanism in the inorganic Q1D superconductor.

  13. Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides

    Science.gov (United States)

    Liu, Qihang; Zunger, Alex

    2017-04-01

    We show that the previously predicted "cubic Dirac fermion," composed of six conventional Weyl fermions including three with left-handed and three with right-handed chirality, is realized in a specific, stable solid state system that has been made years ago, but was not appreciated as a "cubically dispersed Dirac semimetal" (CDSM). We identify the crystal symmetry constraints and find the space group P 63/m as one of the two that can support a CDSM, of which the characteristic band crossing has linear dispersion along the principle axis but cubic dispersion in the plane perpendicular to it. We then conduct a material search using density functional theory, identifying a group of quasi-one-dimensional molybdenum monochalcogenide compounds AI(MoXVI)3 (AI=Na , K, Rb, In, Tl; XVI=S , Se, Te) as ideal CDSM candidates. Studying the stability of the A (MoX) 3 family reveals a few candidates such as Rb (MoTe) 3 and Tl (MoTe) 3 that are predicted to be resilient to Peierls distortion, thus retaining the metallic character. Furthermore, the combination of one dimensionality and metallic nature in this family provides a platform for unusual optical signature—polarization-dependent metallic vs insulating response.

  14. Magnetic properties of a quasi-one-dimensional S=1/2 antiferromagnet: Copper benzoate

    DEFF Research Database (Denmark)

    Dender, D.C.; Davidovic, D.; Reich, D.H.

    1996-01-01

    We use magnetic susceptibility and inelastic neutron scattering measurements to show that copper benzoate, Cu(C6D5COO)(2) . 3D(2)O, is a quasi-one-dimensional S=1/2 antiferromagnet with an exchange constant J=1.57 meV Below T=0.8 K a ferromagnetic contribution to the susceptibility marks the onset...... of canted three-dimensional (3D) antiferromagnetic order. An external magnetic field suppresses this effect, and the susceptibility measured in high held shows only the response of a S=1/2 chain. The dynamic correlation function S((q) over tilde,omega) measured by neutron scattering shows only 1D spin...... correlations for (h) over bar omega greater than or equal to 0.4 meV at T=1.8 K. There is clear evidence of a continuum of magnetic excitations, consistent with the current theoretical picture of the excitation spectrum of the S=1/2 chain at T=0 K....

  15. Spin-orbit coupling in quasi-one-dimensional Wigner crystals

    Science.gov (United States)

    Kornich, Viktoriia; Pedder, Christopher J.; Schmidt, Thomas L.

    2017-01-01

    We study the effect of Rashba spin-orbit coupling (SOC) on the charge and spin degrees of freedom of a quasi-one-dimensional (quasi-1D) Wigner crystal. As electrons in a quasi-1D Wigner crystal can move in the transverse direction, SOC cannot be gauged away in contrast to the pure 1D case. We show that for weak SOC, a partial gap in the spectrum opens at certain ratios between the density of electrons and the inverse Rashba length. We present how the low-energy branch of charge degrees of freedom deviates due to SOC from its usual linear dependence at small wave vectors. In the case of strong SOC, we show that the spin sector of a Wigner crystal cannot be described by an isotropic antiferromagnetic Heisenberg Hamiltonian anymore and that instead the ground state of neighboring electrons is mostly a triplet state. We present a new spin sector Hamiltonian and discuss the spectrum of a Wigner crystal in this limit.

  16. Quasi-one-dimensional density of states in a single quantum ring

    Science.gov (United States)

    Kim, Heedae; Lee, Woojin; Park, Seongho; Kyhm, Kwangseuk; Je, Koochul; Taylor, Robert A.; Nogues, Gilles; Dang, Le Si; Song, Jin Dong

    2017-01-01

    Generally confinement size is considered to determine the dimensionality of nanostructures. While the exciton Bohr radius is used as a criterion to define either weak or strong confinement in optical experiments, the binding energy of confined excitons is difficult to measure experimentally. One alternative is to use the temperature dependence of the radiative recombination time, which has been employed previously in quantum wells and quantum wires. A one-dimensional loop structure is often assumed to model quantum rings, but this approximation ceases to be valid when the rim width becomes comparable to the ring radius. We have evaluated the density of states in a single quantum ring by measuring the temperature dependence of the radiative recombination of excitons, where the photoluminescence decay time as a function of temperature was calibrated by using the low temperature integrated intensity and linewidth. We conclude that the quasi-continuous finely-spaced levels arising from the rotation energy give rise to a quasi-one-dimensional density of states, as long as the confined exciton is allowed to rotate around the opening of the anisotropic ring structure, which has a finite rim width.

  17. Interface-Optical-Phonon Modes in Quasi-one-dimensional Wurtzite Rectangular Quantum Wires

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li

    2006-01-01

    By employing the dielectric continuum model and Loudon's uniaxial crystal model, the interface optical(IO) phonon modes in a freestanding quasi-one-dimensional (Q1D) wurtzite rectangular quantum wire are derived and analyzed. Numerical calculation on a freestanding wurtzite GaN quantum wire is performed. The results reveal that the dispersion frequencies of IO modes sensitively depend on the geometric structures of the Q1D wurtzite rectangular quantum wires, the free wave-number kz in z-direction and the dielectric constant of the nonpolar matrix. The degenerating behavior of the IO modes in Q1D wurtzite rectangular quantum wire has been clearly observed in the case of small wave-number kz and large ratio of length to width of the rectangular crossing profile. The limited frequency behaviors of IO modes have been analyzed deeply, and detailed comparisons with those in wurtzite planar quantum wells and cylindrical quantum wires are also done. The present theories can be looked on as a generalization of that in isotropic rectangular quantum wires, and it can naturally reduce to the case of Q1D isotropic quantum wires once the anisotropy of the wurtzite material is ignored.

  18. Diffusion and structure of a quasi-one-dimensional hard-sphere fluid

    Science.gov (United States)

    Lin, Binhua; Lee, Ji Hwan; Cui, Bianxiao

    2001-03-01

    We report the results of an experimental study of a quasi-one-dimensional hard-sphere fluid. The system consists of uncharged Si colloidal spheres confined in long, uncorrelated 1D-channels whose narrow width forbids mutual passage of spheres along the channel. By tracking the trajectories of the spheres using digital video microscopy, we studied the diffusion and structure of the system as a function of the density of the fluid. Our results show that the behavior of the spheres in self-diffusion is changed gradually from Fickian to non-Fickian near the onset of the collision between the spheres, indicating the correlation between the collision of the hard-spheres and the change in diffusion mechanism. At high density, the self-part of the van Hove function of the system is no longer a Gaussian distribution but a Poisson distribution which can be interpreted using a hydrodynamic analysis for effective wall-drag effect. The pair distribution function of the system can be explained by an analytical expression for a 1D hard-sphere fluid [1]. [1] Y. Rosenfeld, M. Schmidt, H. Lowen and P. Tarazona, Phys. Rev. E 55, 4245 (1997).

  19. Flat bands and PT symmetry in quasi-one-dimensional lattices

    Science.gov (United States)

    Molina, Mario I.

    2015-12-01

    We examine the effect of adding PT -symmetric gain and loss terms to quasi-one-dimensional lattices (ribbons) that possess flat bands. We focus on three representative cases: the Lieb ribbon, the kagome ribbon, and the stub ribbon. In general, we find that the effect on the flat band depends strongly on the geometrical details of the lattice being examined. One interesting result that emerges from an analytical calculation of the band structure of the Lieb ribbon including gain and loss is that its flat band survives the addition of P T symmetry for any amount of gain and loss and also survives the presence of anisotropic couplings. For the other two lattices, any presence of gain and loss destroys their flat bands. For all three ribbons, there are finite stability windows whose size decreases with the strength of the gain and loss parameter. For the Lieb and kagome cases, the size of this window converges to a finite value. The existence of finite stability windows plus the constancy of the Lieb flat band are in marked contrast to the behavior of a pure one-dimensional lattice.

  20. Low-Temperature Properties of Quasi-One-Dimensional Molecule-Based Ferromagnets

    Science.gov (United States)

    Nakanishi, Takashi; Yamamoto, Shoji; Sakai, Tôru

    2001-05-01

    Quantum and thermal behaviors of low-dimensional mixed-spin systems are investigated with particular emphasis on the design of molecule-based ferromagnets. One can obtain a molecular ferromagnet by assembling molecular bricks so as to construct a low-dimensional system with a magnetic ground state and then coupling the chains or the layers again in a ferromagnetic fashion. Two of thus-constructed quasi-one-dimensional bimetallic compounds are qualitatively viewed within the spin-wave treatment, one of which successfully grows into a bulk magnet, while the other of which ends in a singlet ground state. Then, concentrating on the ferrimagnetic arrangement on a two-leg ladder which is well indicative of general coupled-chain ferrimagnets, we develop the spin-wave theory and fully reveal its low-energy structure. We inquire further into the ferromagnetic aspect of the ferrimagnetic ladder numerically calculating the sublattice magnetization and the magnetic susceptibility. There exists a moderate coupling strength between the chains in order to obtain the most ferromagnetic ferrimagnet.

  1. Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

    Science.gov (United States)

    Reichhardt, C.; Reichhardt, C. J. Olson

    2016-09-01

    We numerically examine driven skyrmions interacting with a periodic quasi-one-dimensional substrate where the driving force is applied either parallel or perpendicular to the substrate periodicity direction. For perpendicular driving, the particles in a purely overdamped system simply slide along the substrate minima; however, for skyrmions where the Magnus force is relevant, we find that a rich variety of dynamics can arise. In the single skyrmion limit, the skyrmion motion is locked along the driving or longitudinal direction for low drives, while at higher drives a transition occurs to a state in which the skyrmion moves both transverse and longitudinal to the driving direction. Within the longitudinally locked phase we find a pronounced speedup effect that occurs when the Magnus force aligns with the external driving force, while at the transition to transverse and longitudinal motion, the skyrmion velocity drops, producing negative differential conductivity. For collectively interacting skyrmion assemblies, the speedup effect is still present and we observe a number of distinct dynamical phases, including a sliding smectic phase, a disordered or moving liquid phase, a moving hexatic phase, and a moving crystal phase. The transitions between the dynamic phases produce distinct features in the structure of the skyrmion lattice and in the velocity-force curves. We map these different phases as a function of the ratio of the Magnus term to the dissipative term, the substrate strength, the commensurability ratio, and the magnitude of the driving force.

  2. Size-dependent structural properties of quasi-one-dimensional silicon clusters

    Energy Technology Data Exchange (ETDEWEB)

    Umarova, F.T.; Normurodov, A.B. [Institute of Nuclear Physics, Academy of Sciences, Ulughbek, 102132 Tashkent (Uzbekistan); Turaeva, N.N. [Institute of Polymer Chemistry and Physics, Academy of Sciences, A. Kadyiri str. 7b, 100128 Tashkent (Uzbekistan)

    2012-10-15

    The family of quasi-one-dimensional silicon clusters of regular hexagonal prism form with the layer number n = 2-4 is investigated by the new quantum-chemical tight-binding method. The structural properties of the pristine and hydrogen-passivated clusters are studied as function of cluster sizes. The optimized geometries of clusters show that the layer sizes change with increasing the number of its. The middle layers widen in comparison to the top and bottom layers. The cluster Si{sub 18} trends to the fullerene-like form. Analysis of the quantum-chemical calculation results has been conducted in framework of the correlative approach of Wigner and virial theorem. Electron properties are studied separately for each layer. It has been shown that a distinction in radial compressing forces in different layers and dependence of the distinction values from the layer number (i.e. from cluster size) exist (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Structural and magnetic properties of quasi-one-dimensional doped LiCuVO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Abhishek [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221 005 (India); Kumari, Poonam; Das, A. [Solid State Physics Division, Bhaba Atomic Research Center, Mumbai (India); Dwivedi, G.D. [Department of Physics, Banaras Hindu University, Varanasi 221 005 (India); Shahi, P.; Shukla, K.K. [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221 005 (India); Ghosh, A.K. [Department of Physics, Banaras Hindu University, Varanasi 221 005 (India); Nigam, A.K. [Department of CMP and MS, Tata Institute of Fundamental Research, Mumbai 400 005 (India); Chattopadhyay, K.K. [Department of Physics, Jadavpur University, Kolkata 700032 (India); Chatterjee, Sandip, E-mail: schatterji.app@iitbhu.ac.in [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221 005 (India)

    2013-12-15

    The Neutron diffraction, X-ray photoemission and Magnetic properties of Zn, Co and Mn-doped LiCuVO{sub 4} were investigated. Both with Zn and Co doping the antiferromagnetic correlation increase. On the other hand Mn-doping induces the short range ferromagnetic ordering. Neutron diffraction study does not show any phase transition down to 5 K i.e., there is no indication of long range magnetic ordering. Neutron diffraction study also indicates that with Zn, Co and Mn doping the V–O lengths are changed. Maximum change in the V–O distances is observed for Mn-doped sample. On the other hand, X-ray photoemission spectroscopic data indicates Mn doping converts some Cu{sup 2+} ions into Cu{sup 3+} ions. - Graphical abstract: LiCuVO{sub 4} is a quasi-one-dimensional spin magnet. It shows antiferromagnetic ordering. It is observed when Mn is doped in the Cu site of LiCuVO{sub 4} a short range ferromagnetic ordering occurs. - Highlights: • LiCuVO{sub 4} is an one-dimensional spin chain system. • Mn ion is doped in Cu site to induce ferromagnetism. • Doping of Mn ion changes the Cu–O–Cu bond angle which in effect induces ferromagnetism.

  4. Localization properties of covariant Lyapunov vectors for quasi-one-dimensional hard disks.

    Science.gov (United States)

    Morriss, G P

    2012-05-01

    The Lyapunov exponent spectrum and covariant Lyapunov vectors are studied for a quasi-one-dimensional system of hard disks as a function of density and system size. We characterize the system using the angle distributions between covariant vectors and the localization properties of both Gram-Schmidt and covariant vectors. At low density there is a kinetic regime that has simple scaling properties for the Lyapunov exponents and the average localization for part of the spectrum. This regime shows strong localization in a proportion of the first Gram-Schmidt and covariant vectors and this can be understood as highly localized configurations dominating the vector. The distribution of angles between neighboring covariant vectors has characteristic shapes depending upon the difference in vector number, which vary over the continuous region of the spectrum. At dense gas- or liquid-like densities the behavior of the covariant vectors are quite different. The possibility of tangencies between different components of the unstable manifold and between the stable and unstable manifolds is explored but it appears that exact tangencies do not occur for a generic chaotic trajectory.

  5. Thermodynamic anomaly above the superconducting critical temperature in the quasi-one-dimensional superconductor Ta4Pd3Te16

    Science.gov (United States)

    Helm, T.; Flicker, F.; Kealhofer, R.; Moll, P. J. W.; Hayes, I. M.; Breznay, N. P.; Li, Z.; Louie, S. G.; Zhang, Q. R.; Balicas, L.; Moore, J. E.; Analytis, J. G.

    2017-02-01

    We study the intrinsic electronic anisotropy and fermiology of the quasi-one-dimensional superconductor Ta4Pd3Te16 . Below T*=20 K, we detect a thermodynamic phase transition that predominantly affects the conductivity perpendicular to the quasi-one-dimensional chains. The transition relates to the presence of charge order that precedes superconductivity. Remarkably, the Fermi surface pockets detected by de Haas-van Alphen oscillations are unaffected by this transition, suggesting that the ordered state does not break any translational symmetries but rather alters the scattering of the quasiparticles themselves.

  6. Effects of temperature and pressure on morphologies of quasi-one-dimensional ZnO nanostructures fabricated via thermal evaporation

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-cheng; CAI Wei; MENG Xiang-long

    2006-01-01

    Quasi one-dimensional zinc oxide nanomaterials were synthesized by thermal evaporation. The structure,morphologies and composition of ZnO nanomaterials prepared under different conditions were studied by XRD,TEM,SEM and EDX. The morphologies are strongly sensitive to the temperature and the pressure during growth,including nanowires,nanobelts,nanocombs and pyramidal-like nanomaterials.

  7. Thermally induced local failures in quasi-one-dimensional systems: collapse in carbon nanotubes, neckling in nanowires, bubbles in DNA

    Energy Technology Data Exchange (ETDEWEB)

    Nisoli, Cristiano [Los Alamos National Laboratory; Lookman, Turab [Los Alamos National Laboratory; Saxena, Avadh [Los Alamos National Laboratory; Abraham, Douglas [RUDOLF PEIERLS CENTRE

    2009-01-01

    Quasi one dimensional systems can suffer local structural failures-broadly defined-along their length: for instance, carbon nanotubes can collapse, nanowires can show bottlenecks below which conductance drops, bubbles open in DNA. We present a formalism to explore the occurrence of those thermally activated failures in complete generality, to calculate the average length between them as a function of the thermodynamic observables.

  8. Oxygen hole pairing in CuO2 planes : a quasi-one dimensional case

    Science.gov (United States)

    Feinberg, D.; Avignon, M.; Boiron, M.; Chakraverty, B. K.

    A possible mechanism of pairing of oxygen holes produced on doping is investigated. These holes are formed due to strong correlation energy on copper sites. In a simplified CuO2-sheet band structure, they are showed to take place in a narrow p-oxygen band originating from the broadening of a non-bonding p-oxygen level by direct O-O transfer. Such a band shows a quasi-one-dimensional density of states N (E) ˜ E- 1/2, which strongly enhances BCS-type pairing. Tc is evaluated for both s and d pairing and varies as tλ 2 where λ is the coupling constant and t the O-O transfer integral. On examine la possibilité d'appariement de trous sur les oxygènes, produits lors du dopage. Ces trous sont formés du fait des fortes corrélations sur les sites de cuivre. Dans une structure de bande simplifiée, pour les plans CuO2, on montre qu'ils se forment dans une étroite bande p d'oxygène issue de l'élargissement d'un niveau p non-liant par transfert direct O-O. Une telle bande possède une densité d'états quasi-unidimensionnelle N (E) ˜ E-1/2, ce qui favorise fortement l'appariement de type BCS. Tc est évaluée dans le cas d'un appariement s et d et varie comme tλ2 où λ est la constante de couplage et t l'intégrale de transfert O-O.

  9. Size effects in electrical and magnetic properties of quasi-one-dimensional tin wires in asbestos

    Science.gov (United States)

    Chernyaev, A. V.; Shamshur, D. V.; Fokin, A. V.; Kalmykov, A. E.; Kumzerov, Yu. A.; Sorokin, L. M.; Parfen'ev, R. V.; Lashkul, A.

    2016-03-01

    Bulk composites have been prepared based on one-dimensional fibers of natural chrisothil-asbestos with various internal diameters ( d = 6-2.5 nm) filled with tin. The electrical and magnetic properties of quasi-one-dimensional Sn wires have been studied at low temperatures. The electrical properties have been measured at T = 300 K at a pressure P = 10 kbar. It has been found that the superconducting (SC) characteristics of the nanocomposites (critical temperature T c and critical magnetic field H c) increase as the Sn filament diameter decreases. The temperature spreading of the resistive SC transition also increases as the Sn filament diameter decreases, which is explained by the SC order parameter fluctuations. The size effects (the increase in critical temperature T c and transition width Δ T c) in Sn nanofilaments are well described by the independent Aslamazov-Larkin and Langer-Ambegaokara fluctuation theories, which makes it possible to find the dependence of T c of the diffuse SC transition on the nanowire diameter. Using the temperature and magnetic-field dependences of the magnetic moment M( T, H), it has been found that the superconductor-normal metal phase diagram of the Sn-asbestos nanocomposite has a wider region of the SC state in T and H as compared to the data for bulk Sn. The magnetic properties of chrisotil-asbestos fibers unfilled with Sn have been studied. It has been found that the Curie law is fulfilled and that the superparamagnetism is absent in such samples. The obtained results indicate the absence of magnetically ordered impurities (magnetite) in the chrisotil-asbestos matrix, which allowed one to not consider the problem of the interaction of the magnetic subsystem of the asbestos matrix and the superconducting subsystem of Sn nanowires.

  10. Focus on Organic Conductors

    OpenAIRE

    Shinya Uji, Takehiko Mori and Toshihiro Takahashi

    2009-01-01

    Organic materials are usually thought of as electrical insulators. Progress in chemical synthesis, however, has brought us a rich variety of conducting organic materials, which can be classified into conducting polymers and molecular crystals. Researchers can realize highly conducting molecular crystals in charge-transfer complexes, where suitable combinations of organic electron donor or acceptor molecules with counter ions or other organic molecules provide charge carriers. By means of a ki...

  11. Photoinduced Change in the Charge Order Pattern in the Quarter-Filled Organic Conductor (EDO-TTF)2PF6 with a Strong Electron-Phonon Interaction

    Science.gov (United States)

    Onda, Ken; Ogihara, Sho; Yonemitsu, Kenji; Maeshima, Nobuya; Ishikawa, Tadahiko; Okimoto, Yoichi; Shao, Xiangfeng; Nakano, Yoshiaki; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-Ya

    2008-08-01

    The quasistable state in the photoinduced phase transition for the quasi-one-dimensional quarter-filled organic conductor (EDO-TTF)2PF6 has been examined by ultrafast reflective measurements and time-dependent model calculations incorporating both electron-electron and electron-phonon interactions. The transient optical conductivity spectrum over a wide probe photon-energy range revealed that photoexcitation induced a new type of charge-disproportionate state. Additionally, coherent and incoherent oscillations dependent on probe photon energies were found, as predicted by the calculation.

  12. The Hall effect in the organic conductor TTF–TCNQ: choice of geometry for accurate measurements of a highly anisotropic system

    DEFF Research Database (Denmark)

    Tafra, E; Čulo, M; Basletić, M

    2012-01-01

    We have measured the Hall effect on recently synthesized single crystals of the quasi-one-dimensional organic conductor TTF–TCNQ (tetrathiafulvalene–tetracyanoquinodimethane), a well known charge transfer complex that has two kinds of conductive stacks: the donor (TTF) and the acceptor (TCNQ......) chains. The measurements were performed in the temperature interval 30 K ... Hall effect measurements. Our results show, contrary to past belief, that the Hall coefficient does not depend on the geometry of measurements and that the Hall coefficient value is approximately zero in the high temperature region (T > 150 K), implying that there is no dominance of either the TTF...

  13. Quantum-chemical studies of quasi-one-dimensional electron systems. Part 2. Cumulenes and origin of the forbidden zone

    Directory of Open Access Journals (Sweden)

    Yuriy Kruglyak

    2015-06-01

    Full Text Available This review is devoted to the basic problem in quantum theory of quasi-one-dimensional electron systems like polyenes (Part 1 and cumulenes (Part 2 – physical origin of the forbidden zone in these and analogous 1D electron systems due to two possible effects – Peierls instability (bond alternation and Mott instability (electron correlation. Both possible contradiction and coexistence of the Mott and Peierls instabilities are summerized on the basis of the Kiev quantum chemistry team research projects.

  14. Photophysics of quasi-one-dimensional excitons in pi-conjugated polymers and semiconducting single-walled carbon nanotubes

    Science.gov (United States)

    Sheng, Chuanxiang

    , illustrating the universal features of quasi-one-dimensional excitons in carbon-based pi-conjugated systems. In both cases PA1 gives the lower limit of the binding energy of the lowest optical exciton. The binding energy of lowest exciton belonging to the widest S-NTs with diameters ≥ 1 nm in films is 0.3-0.4 eV, as well as ˜ 0.9 eV in PPV polymers.

  15. Voltage plateaus on V( I) curves of long quasi-one-dimensional superconducting wires (without microwave irradiation)

    Science.gov (United States)

    Kuznetsov, V. I.; Firsov, A. A.

    2016-11-01

    Segments of an almost constant voltage (plateaus) on the V( I) curves of long quasi-one-dimensional superconducting aluminum wires placed in a magnetic field are found slightly below T c, which are unexpected at the parameters and geometry considered in this work. These plateaus are assumingly attributed to subharmonics of the superconducting gap and are due to multiple Andreev reflection and strong quasiparticle heating, which occur in the nonequilibrium region of a wire. The plateaus indicate the coexistence of superconductivity and dissipation in these wires. These results cannot be described by the existing theories.

  16. Quasi-one-dimensional impurity states in Ga sub 1 minus x Al sub x As/GaAs heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Ghazali, A. (Groupe de Physique de Solides, Univ. de Paris 7 et Paris 6, Unite Associee au CNRS, No. 17, Tour 23 2 Place Jussieu, F-75251, Paris Cedex 05 (FR)); da Cunha Lima, I.C. (Associado de Sensores e Materials, Inst. Nacional de Pesquisas Espaciais, CP 515, 12.201 Sao Jose dos Campos, Sao Paulo (BR))

    1992-04-30

    The advances in submicron lithography on semiconductor devices allow to produce very narrow inversion channels in which the electron gas behaves as quasi-one-dimensional. The presence of shallow donor impurities introduces bound states for electrons which have their binding energies depending on the impurity location in the plane perpendicular to the channel. In this paper, the authors calculate these binding energies and plot the iso-energy curves for the dilute regime, assuming a confinement potential separable into a square well (caused by the barriers at the interfaces creating the quantum well) and an electrically induced harmonic potential in a direction perpendicular to the growth axis.

  17. Revealing origin of quasi-one dimensional current transport in defect rich two dimensional materials

    Energy Technology Data Exchange (ETDEWEB)

    Lotz, Mikkel R.; Boll, Mads; Bøggild, Peter; Petersen, Dirch H., E-mail: dirch.petersen@nanotech.dtu.dk [Center for Nanostructured Graphene (CNG), Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark); Hansen, Ole [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark); Danish National Research Foundation' s Center for Individual Nanoparticle Functionality (CINF), Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Kjær, Daniel [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark); CAPRES A/S, Scion-DTU, Building 373, DK-2800 Kgs. Lyngby (Denmark)

    2014-08-04

    The presence of defects in graphene have for a long time been recognized as a bottleneck for its utilization in electronic and mechanical devices. We recently showed that micro four-point probes may be used to evaluate if a graphene film is truly 2D or if defects in proximity of the probe will lead to a non-uniform current flow characteristic of lower dimensionality. In this work, simulations based on a finite element method together with a Monte Carlo approach are used to establish the transition from 2D to quasi-1D current transport, when applying a micro four-point probe to measure on 2D conductors with an increasing amount of line-shaped defects. Clear 2D and 1D signatures are observed at low and high defect densities, respectively, and current density plots reveal the presence of current channels or branches in defect configurations yielding 1D current transport. A strong correlation is found between the density filling factor and the simulation yield, the fraction of cases with 1D transport and the mean sheet conductance. The upper transition limit is shown to agree with the percolation threshold for sticks. Finally, the conductance of a square sample evaluated with macroscopic edge contacts is compared to the micro four-point probe conductance measurements and we find that the micro four-point probe tends to measure a slightly higher conductance in samples containing defects.

  18. Magnetic excitation spectra of strongly correlated quasi-one-dimensional systems: Heisenberg versus Hubbard-like behavior

    Science.gov (United States)

    Nocera, A.; Patel, N. D.; Fernandez-Baca, J.; Dagotto, E.; Alvarez, G.

    2016-11-01

    We study the effects of charge degrees of freedom on the spin excitation dynamics in quasi-one-dimensional magnetic materials. Using the density matrix renormalization group method, we calculate the dynamical spin structure factor of the Hubbard model at half electronic filling on a chain and on a ladder geometry, and compare the results with those obtained using the Heisenberg model, where charge degrees of freedom are considered frozen. For both chains and two-leg ladders, we find that the Hubbard model spectrum qualitatively resembles the Heisenberg spectrum—with low-energy peaks resembling spinonic excitations—already at intermediate on-site repulsion as small as U /t ˜2 -3 , although ratios of peak intensities at different momenta continue evolving with increasing U /t converging only slowly to the Heisenberg limit. We discuss the implications of these results for neutron scattering experiments and we propose criteria to establish the values of U /t of quasi-one-dimensional systems described by one-orbital Hubbard models from experimental information.

  19. First-principles investigation of exchange interactions in quasi-one-dimensional antiferromagnet CaV2O4

    Science.gov (United States)

    Pchelkina, Z. V.; Solovyev, I. V.

    2015-01-01

    The effects of orbital degrees of freedom on the exchange interactions in a quasi-one-dimensional spin-1 antiferromagnet CaV2O4 are systematically studied. For this purpose a realistic low-energy electron model with the parameters derived from the first-principles calculations is constructed in the Wannier basis for the t2g bands. The exchange interactions are calculated using both the theory of infinitesimal spin rotations near the mean-field ground state and the superexchange model, which provide a consistent description. The obtained behaviour of exchange interactions differs substantially from the previously proposed phenomenological picture based on magnetic measurements and structural considerations, namely: (i) despite the quasi-one-dimensional character of the crystal structure, consisting of the zigzag chains of the edge-sharing VO6 octahedra, the electronic structure is essentially three-dimensional, that leads to finite interactions between the chains; (ii) the exchange interactions along the legs of the chains appear to dominate; and (iii) there is a substantial difference in exchange interactions in two crystallographically inequivalent chains. The combination of these three factors successfully reproduces the behaviour of experimental magnetic susceptibility.

  20. On the quasi-one dimensional structure of the cellular detonation in a two-dimensional duct

    Science.gov (United States)

    Uyeda, C. M.; Kurosaka, M.; Ferrante, A.

    2015-11-01

    We performed numerical simulations of cellular detonations in a 2D duct to establish the validity of the one-dimensional ZND model. The detonation was simulated by solving the Euler equations with a WENO-TCD numerical method using adaptive mesh refinement and a detailed chemical reaction mechanism. The results show that the properties of the ZND model of a 2H2-O2-7Ar reaction are very close to the results of the simulations initiated using three different methods for the area-averaged properties and the properties of particles tracked along their pathlines. Disagreements between the particle properties and the ZND model are greatest near the detonation front where the transverse wave and Mach stem introduce larger jumps in the flow properties than the ZND model predicts. The particle pathlines also exhibit a quasi one-dimensional motion downstream from the detonation front which is supported by the quick decay in the particles' velocity ratio of the vertical to horizontal velocity components, in the reference frame attached to the detonation front. These findings show the quasi one-dimensional nature of 2D detonations and the applicability of the ZND model.

  1. History of crystalline organic conductor

    Science.gov (United States)

    Murata, Keizo

    2017-05-01

    A brief view of crystalline organic conductor is presented. Since the discovery of TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane) in the mid 1970’s, pressure has been an indispensable tool to develop the physics of this field. From the aspect of charge transfer salt, TTF-TCNQ and its family was specified with partial charge transfer, two chain one-dimensional (1D) system, charge density wave (CDW) and commensurability. On the other hand, in (TMTSF)2X family (TMTSF: tetramethyltetraselenafulvalene, X: electron acceptor such as PF6, ClO4), complete charge transfer, one chain system, spin density wave (SDW), field-induced SDW, quantum Hall effect, superconductivity were discussed. Further, together with pressure itself, cooling rate was noticed to be important for low temperature properties. Recently, coming back to TTF-TCNQ family, i.e., HMTSF-TCNQ, whether or not field-induced CDW, instead of field-induced SDW, and quantum Hall effect is present was discussed (HMTSF: hexamethylene-tetraselenafulvalene). Whether or not the Fermiology in (TMTTF)2X under pressure is similar to that of (TMTSF)2X is discussed as well. In (BEDT-TTF)2X, new aspect of macroscopic polarization of α-(BEDT-TTF)2I3 related to charge order is described. At the end, in contrast to the charge transfer salts, non-charge transfer salt, that is, single component conductor is presented as a new possible example of Dirac cone, which was deeply studied by many researchers in α-(BEDT-TTF)2I3, together with the theoretical calculation of its magnetic susceptibility (BEDT-TTF: bisethylenedithia-tetrathiafulvalene).

  2. Order-disorder quantum phase transition in the quasi-one-dimensional spin-1/2 collinear antiferromagnetic Heisenberg model.

    Science.gov (United States)

    Rufo, Sabrina; Mendonça, Griffith; Plascak, J A; de Sousa, J Ricardo

    2013-09-01

    The ground-state properties of the quasi-one-dimensional spin-1/2 antiferromagnetic Heisenberg model is investigated by using a variational method. Spins on chains along the x direction are antiferromagnetically coupled with exchange J>0, while spins between chains in the y direction are coupled either ferromagnetically (J' 0). The staggered and the colinear antiferromagnetic magnetizations are computed and their dependence on the anisotropy parameter λ=|J'|/J is analyzed. It is found that an infinitesimal interchain coupling parameter is sufficient to stabilize a long-range order with either a staggered magnetization m_{s} (J' > 0) or a colinear antiferromagnetic magnetization m_{caf} (J' < 0), both behaving as ≃λ¹/² for λ → 0.

  3. Drag force on an impurity below the superfluid critical velocity in a quasi-one-dimensional Bose-Einstein condensate.

    Science.gov (United States)

    Sykes, Andrew G; Davis, Matthew J; Roberts, David C

    2009-08-21

    The existence of frictionless flow below a critical velocity for obstacles moving in a superfluid is well established in the context of the mean-field Gross-Pitaevskii theory. We calculate the next order correction due to quantum and thermal fluctuations and find a nonzero force acting on a delta-function impurity moving through a quasi-one-dimensional Bose-Einstein condensate at all subcritical velocities and at all temperatures. The force occurs due to an imbalance in the Doppler shifts of reflected quantum fluctuations from either side of the impurity. Our calculation is based on a consistent extension of Bogoliubov theory to second order in the interaction strength, and finds new analytical solutions to the Bogoliubov-de Gennes equations for a gray soliton. Our results raise questions regarding the quantum dynamics in the formation of persistent currents in superfluids.

  4. Electronic structure of quasi-one-dimensional superconductor K2Cr3As3 from first-principles calculations

    Science.gov (United States)

    Jiang, Hao; Cao, Guanghan; Cao, Chao

    2015-11-01

    The electronic structure of quasi-one-dimensional superconductor K2Cr3As3 is studied through systematic first-principles calculations. The ground state of K2Cr3As3 is paramagnetic. Close to the Fermi level, the , dxy, and orbitals dominate the electronic states, and three bands cross EF to form one 3D Fermi surface sheet and two quasi-1D sheets. The electronic DOS at EF is less than 1/3 of the experimental value, indicating a large electron renormalization factor around EF. Despite of the relatively small atomic numbers, the antisymmetric spin-orbit coupling splitting is sizable (≈60 meV) on the 3D Fermi surface sheet as well as on one of the quasi-1D sheets. Finally, the imaginary part of bare electron susceptibility shows large peaks at Γ, suggesting the presence of large ferromagnetic spin fluctuation in the compound.

  5. Structural study of quasi-one-dimensional vanadium pyroxene LiVSi2O6 single crystals

    Science.gov (United States)

    Ishii, Yuto; Matsushita, Yoshitaka; Oda, Migaku; Yoshida, Hiroyuki

    2017-02-01

    Single crystals of quasi-one-dimensional vanadium pyroxene LiVSi2O6 were synthesized and the crystal structures at 293 K and 113 K were studied using X-ray diffraction experiments. We found a structural phase transition from the room-temperature crystal structure with space group C2/c to a low-temperature structure with space group P21/c, resulting from a rotational displacement of SiO4 tetrahedra. The temperature dependence of magnetic susceptibility shows a broad maximum around 116 K, suggesting an opening of the Haldane gap expected for one-dimensional antiferromagnets with S=1. However, an antiferromagnetic long-range order was developed below 24 K, probably caused by a weak inter-chain magnetic coupling in the compound.

  6. Giant Nernst effect and bipolarity in the quasi-one-dimensional metal Li0.9Mo6O17.

    Science.gov (United States)

    Cohn, J L; White, B D; dos Santos, C A M; Neumeier, J J

    2012-02-03

    The Nernst coefficient for the quasi-one-dimensional metal, Li{0.9}Mo{6}O{17}, is found to be among the largest known for metals (ν≃500  μV/KT at T∼20  K), and is enhanced in a broad range of temperature by orders of magnitude over the value expected from Boltzmann theory for carrier diffusion. A comparatively small Seebeck coefficient implies that Li{0.9}Mo{6}O{17} is bipolar with large, partial Seebeck coefficients of opposite sign. A very large thermomagnetic figure of merit, ZT∼0.5, is found at high field in the range T≈35-50  K.

  7. Hall effect in the normal phase of the organic superconductor (TMTSF)2PF6

    DEFF Research Database (Denmark)

    Moser, J.; Cooper, J.R.; Jerome, D.

    2000-01-01

    We report accurate Hall effect measurements performed in the normal phase of the quasi-one-dimensional organic conductor (TMTSF)(2)PF(6) at ambient pressure. The Hall coefficient is found to be strongly temperature dependent all the way from 300 K down to the spin density wave onset arising aroun...

  8. Statics and dynamics of quasi one-dimensional Bose-Einstein condensate in harmonic and dimple trap

    Science.gov (United States)

    Akram, Javed; Pelster, Axel

    2016-06-01

    We investigate a quasi one-dimensional {{}87}\\text{Rb} Bose-Einstein condensate in a harmonic trap with an additional dimple trap (dT) in the center. Within a zero-temperature Gross-Pitaevskii mean-field description we provide a one-dimensional physical intuitive model, which we solve by both a time-independent variational approach and numerical calculations. With this we obtain at first equilibrium results for the emerging condensate wave function which reveal that a dimple trap potential induces a bump or a dip in case of a red- or a blue-detuned Gaussian laser beam, respectively. Afterwards, we investigate how this dT induced bump/dip-imprint upon the condensate wave function evolves for two quench scenarios. At first we consider the generic case that the harmonic confinement is released. During the resulting time-of-flight expansion it turns out that the dT induced bump in the condensate wave function remains present, whereas the dip starts decaying after a characteristic time scale which decreases with increasing blue-detuned dT depth. Secondly, once the red- or blue-detuned dT is switched off, we find that bright shock-waves or gray/dark bi-soliton trains emerge which oscillate within the harmonic confinement with a characteristic frequency.

  9. Synthesis,M(o)ssbauer Spectra and Magnetic Properties of Quasi-One-Dimensional Fe3O4 Nanowires

    Institute of Scientific and Technical Information of China (English)

    薛德胜; 张丽英; 高存绪; 许雪飞; 桂安标

    2004-01-01

    Quasi-one-dimensional Fe3O4 nanowires in diameter of about 200nm were assembled into anodic aluminium oxide templates via electrodepositing and heat-treating processes. The nanowires have a polycrystalline spinel structure with a = 8.317A, and each nanowire is composed of fine Fe3O4 crystallites with size of about 30nm.The magnetic moments of Fe3 O4 crystallites in nanowires have a preferred orientation leaning to the wire axis but not parallel to the wire axis. Mossbauer spectra (MS) were used to verify the presence of Fe3 O4 further and the existence of superparamagnetic particles in nanowires. A perpendicular magnetic anisotropy was observed obviously. Temperature dependence of the magnetic moments (M-T) shows that the Verwey transition for the Fe3 O4 nanowires occurs at 50 K, and the behaviour of the M-T curve is different from that of other magnetite materials. These characteristic magnetic properties of Fe3 O4 nanowires are mainly due to the reduced dimension and the configuration of preferred orientation in the nanowires caused by the shape anisotropy.

  10. A novel quasi-one-dimensional topological insulator in bismuth iodide β-Bi4I4

    Science.gov (United States)

    Autès, Gabriel; Isaeva, Anna; Moreschini, Luca; Johannsen, Jens C.; Pisoni, Andrea; Mori, Ryo; Zhang, Wentao; Filatova, Taisia G.; Kuznetsov, Alexey N.; Forró, László; van den Broek, Wouter; Kim, Yeongkwan; Kim, Keun Su; Lanzara, Alessandra; Denlinger, Jonathan D.; Rotenberg, Eli; Bostwick, Aaron; Grioni, Marco; Yazyev, Oleg V.

    2016-02-01

    Recent progress in the field of topological states of matter has largely been initiated by the discovery of bismuth and antimony chalcogenide bulk topological insulators (TIs; refs ,,,), followed by closely related ternary compounds and predictions of several weak TIs (refs ,,). However, both the conceptual richness of Z2 classification of TIs as well as their structural and compositional diversity are far from being fully exploited. Here, a new Z2 topological insulator is theoretically predicted and experimentally confirmed in the β-phase of quasi-one-dimensional bismuth iodide Bi4I4. The electronic structure of β-Bi4I4, characterized by Z2 invariants (1;110), is in proximity of both the weak TI phase (0;001) and the trivial insulator phase (0;000). Our angle-resolved photoemission spectroscopy measurements performed on the (001) surface reveal a highly anisotropic band-crossing feature located at the point of the surface Brillouin zone and showing no dispersion with the photon energy, thus being fully consistent with the theoretical prediction.

  11. Efficient three-photon excitation of quasi-one-dimensional strontium Rydberg atoms with n ˜300

    Science.gov (United States)

    Ye, S.; Zhang, X.; Dunning, F. B.; Yoshida, S.; Hiller, M.; Burgdörfer, J.

    2014-07-01

    The efficient production of very-high-n, n ˜300, quasi-one-dimensional (quasi-1D) strontium Rydberg atoms through three-photon excitation of extreme Stark states in the presence of a weak dc field is demonstrated using a crossed laser-atom beam geometry. Strongly polarized quasi-1D states with large permanent dipole moments ˜1.2n2 a.u. can be created in the beam at densities (˜106 cm-3) where dipole blockade effects should become important. A further advantage of three-photon excitation is that the product F states are sensitive to the presence of external fields, allowing stray fields to be reduced to very small values. The experimental data are analyzed using quantum calculations based on a two-active-electron model together with classical trajectory Monte Carlo simulations. These allow determination of the atomic dipole moments and confirm that stray fields can be reduced to ≤25μV cm-1.

  12. Time-dependent mode structure for Lyapunov vectors as a collective movement in quasi-one-dimensional systems.

    Science.gov (United States)

    Taniguchi, Tooru; Morriss, Gary P

    2005-01-01

    The time-dependent mode structure of the Lyapunov vectors associated with the stepwise structure of the Lyapunov spectra and its relation to the momentum autocorrelation function are discussed in quasi-one-dimensional many-hard-disk systems. We obtain the complete mode structures (Lyapunov modes) for all components of the Lyapunov vectors, including the longitudinal and transverse components of both the spatial and momentum parts, and their phase relations. These mode structures are suggested by the form of the Lyapunov vectors for the zero-Lyapunov exponents. The spatial node structures of these modes are explained by the reflection properties of the hard walls used in the models. Our main result is that the largest time-oscillating period of the Lyapunov modes is twice as long as the time-oscillating period of the longitudinal momentum autocorrelation function. This relation is satisfied irrespective of the number of particles and the boundary conditions. A simple explanation for this relation is given based on the form of the time-dependent Lyapunov mode.

  13. Conduction in rectangular quasi-one-dimensional and two-dimensional random resistor networks away from the percolation threshold.

    Science.gov (United States)

    Kiefer, Thomas; Villanueva, Guillermo; Brugger, Jürgen

    2009-08-01

    In this study we investigate electrical conduction in finite rectangular random resistor networks in quasione and two dimensions far away from the percolation threshold p(c) by the use of a bond percolation model. Various topologies such as parallel linear chains in one dimension, as well as square and triangular lattices in two dimensions, are compared as a function of the geometrical aspect ratio. In particular we propose a linear approximation for conduction in two-dimensional systems far from p(c), which is useful for engineering purposes. We find that the same scaling function, which can be used for finite-size scaling of percolation thresholds, also applies to describe conduction away from p(c). This is in contrast to the quasi-one-dimensional case, which is highly nonlinear. The qualitative analysis of the range within which the linear approximation is legitimate is given. A brief link to real applications is made by taking into account a statistical distribution of the resistors in the network. Our results are of potential interest in fields such as nanostructured or composite materials and sensing applications.

  14. The Hall effect in the organic conductor TTF-TCNQ: choice of geometry for accurate measurements of a highly anisotropic system.

    Science.gov (United States)

    Tafra, E; Culo, M; Basletić, M; Korin-Hamzić, B; Hamzić, A; Jacobsen, C S

    2012-02-01

    We have measured the Hall effect on recently synthesized single crystals of the quasi-one-dimensional organic conductor TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane), a well known charge transfer complex that has two kinds of conductive stacks: the donor (TTF) and the acceptor (TCNQ) chains. The measurements were performed in the temperature interval 30 K Hall effect measurements. Our results show, contrary to past belief, that the Hall coefficient does not depend on the geometry of measurements and that the Hall coefficient value is approximately zero in the high temperature region (T > 150 K), implying that there is no dominance of either the TTF or the TCNQ chain. At lower temperatures our measurements clearly prove that all three phase transitions of TTF-TCNQ could be identified from Hall effect measurements.

  15. Neutron scattering and μSR investigations of quasi-one-dimensional magnetism in the spin =3/2 compound Li3RuO4

    DEFF Research Database (Denmark)

    Manuel, P.; Adroja, D. T.; Lindgård, Per-Anker

    2011-01-01

    The S = 3/2, quasi-one-dimensional (1D) zig-zag chain Heisenberg antiferromagnet Li3RuO4 has been investigated using heat capacity, inelastic neutron scattering, neutron diffraction, and μSR measurements on a powder sample. Our neutron diffraction and μSR studies confirm a long-range ordering of ...

  16. Néel to spin-Peierls transition in a quasi-one-dimensional Heisenberg model coupled to bond phonons

    Science.gov (United States)

    Pillay, Jason Cornelius; Wierschem, Keola; Sengupta, Pinaki

    2013-08-01

    The zero and finite temperature spin-Peierls transitions in a quasi-one-dimensional spin-(1)/(2) Heisenberg model coupled to adiabatic bond phonons is investigated using the stochastic series expansion (SSE) quantum Monte Carlo (QMC) method. The quantum phase transition from a gapless Néel state to a spin-gapped Peierls state is studied in the parameter space spanned by spatial anisotropy, interchain coupling strength, and spin-lattice coupling strength. It is found that for any finite interchain coupling, the transition to a dimerized Peierls ground state only occurs when the spin-lattice coupling exceeds a finite, nonzero critical value. This is in contrast to the pure 1D model (zero interchain coupling), where adiabatic/classical phonons lead to a dimerized ground state for any nonzero spin-phonon interaction. The phase diagram in the parameter space shows that for a strong interchain coupling, the relation between the interchain coupling and the critical value of the spin-phonon interaction is linear whereas for weak interchain coupling, this behavior is found to have a natural logarithmlike relation. No region was found to have a long range magnetic order and dimerization occurring simultaneously. Instead, the Néel state order vanishes simultaneously with the setting in of the spin-Peierls state. For the thermal phase transition, a continuous heat capacity with a peak at the critical temperature Tc shows a second order phase transition. The variation of the equilibrium bond length distortion δeq with temperature showed a power law relation which decayed to zero as the temperature was increased to Tc, indicating a continuous transition from the dimerized phase to a paramagnetic phase with uniform bond length and zero antiferromagnetic susceptibility.

  17. Impurity-limited resistance and phase interference of localized impurities under quasi-one dimensional nano-structures

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Nobuyuki, E-mail: sano@esys.tsukuba.ac.jp [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)

    2015-12-28

    The impurity-limited resistance and the effect of the phase interference among localized multiple impurities in the quasi-one dimensional (quasi-1D) nanowire structures are systematically investigated under the framework of the scattering theory. We derive theoretical expressions of the impurity-limited resistance in the nanowire under the linear response regime from the Landauer formula and from the Boltzmann transport equation (BTE) with the relaxation time approximation. We show that the formula from the BTE exactly coincides with that from the Landauer approach with the weak-scattering limit when the energy spectrum of the in-coming electrons from the reservoirs is narrow and, thus, point out a possibility that the distinction of the impurity-limited resistances derived from the Landauer formula and that of the BTE could be made clear. The derived formulas are applied to the quasi-1D nanowires doped with multiple localized impurities with short-range scattering potential and the validity of various approximations on the resistance are discussed. It is shown that impurity scattering becomes so strong under the nanowire structures that the weak-scattering limit breaks down in most cases. Thus, both phase interference and phase randomization simultaneously play a crucial role in determining the impurity-limited resistance even under the fully coherent framework. When the impurity separation along the wire axis direction is small, the constructive phase interference dominates and the resistance is much greater than the average resistance. As the separation becomes larger, however, it approaches the series resistance of the single-impurity resistance due to the phase randomization. Furthermore, under the uniform configuration of impurities, the space-average resistance of multiple impurities at room temperature is very close to the series resistance of the single-impurity resistance, and thus, each impurity could be regarded as an independent scattering center. The

  18. Magnetic structure and spin dynamics of the quasi-one-dimensional spin-chain antiferromagnet BaCo2V2O8

    DEFF Research Database (Denmark)

    Kawasaki, Yu; Gavilano, Jorge L.; Keller, Lukas

    2011-01-01

    We report a neutron diffraction and muon spin relaxation mu SR study of static and dynamical magnetic properties of BaCo2V2O8, a quasi-one-dimensional spin-chain system. A proposed model for the antiferromagnetic structure includes: a propagation vector (k) over right arrow (AF) = (0,0,1), indepe......We report a neutron diffraction and muon spin relaxation mu SR study of static and dynamical magnetic properties of BaCo2V2O8, a quasi-one-dimensional spin-chain system. A proposed model for the antiferromagnetic structure includes: a propagation vector (k) over right arrow (AF) = (0...... at different muon stopping sites. Muon time spectra measured at weak longitudinal fields and temperatures much higher than T-N can be well described using a single muon site with an exponential muon spin relaxation that gradually changes into an stretched exponential on approaching T-N. The temperature...

  19. Hall effect in organic layered conductors

    Directory of Open Access Journals (Sweden)

    R.A.Hasan

    2006-01-01

    Full Text Available The Hall effect in organic layered conductors with a multisheeted Fermi surfaces was considered. It is shown that the experimental study of Hall effect and magnetoresistance anisotropy at different orientations of current and a quantizing magnetic field relative to the layers makes it possible to determine the contribution of various charge carriers groups to the conductivity, and to find out the character of Fermi surface anisotropy in the plane of layers.

  20. 准一维ZnO纳米材料及器件的研究进展%Progress in Quasi One Dimensional ZnO Nanomaterials and Nanodevices

    Institute of Scientific and Technical Information of China (English)

    段理; 樊小勇; 李东林

    2011-01-01

    The quasi one dimensional nanostructural ZnO have potential applications in micro-electronics and optoelectronics devices. In recent years, the studies of one dimensional ZnO nanodevices design and nanofabrication have started. The fabrication methods and mechanisms of quasi one dimensional ZnO nanomaterials and nanoarrays are summarized. The progress of quasi one dimensional ZnO nanodevices is also introduced. The existing problems and the future research tasks are presented in the end.%准一维纳米ZnO因在微电子和光电子领域具有广阔前景而受到关注.综述了近年来准一维ZnO纳米材料的主流制备方法及其相关机理,介绍了一维纳米阵列的实现方案,总结了各类准一维ZnO纳米器件的研究进展,探讨了研究现状并展望了未来的研究方向.

  1. High-frequency magneto-conductivity studies of low-dimensional organic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Schrama, J.M

    2000-07-01

    In this thesis I present experimental studies of the millimetre-wave magneto-conductivity of the organic charge-transfer salts {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}, {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} and (TMTSF){sub 2}ClO{sub 4}. A rotating resonant cavity insert was developed to investigate the angle dependence of resonances in the magneto-conductivity. The technique revealed a new kind of magnetic resonance, the Fermi-surface traversal resonance (FTR), which is described by a semiclassical model. The FTRs give information about the topology of the quasi-one-dimensional (Q1D) Fermi-surface sections. The Q1D Fermi-surface sections play an important role in forming the ground states in organic conductors giving rise, for example, to nesting associated with a density-wave. Chapter 1 gives a brief historical overview of the development of organic conductors and provides basic information about crystal structures and Fermi surfaces of BEDT-TTF based systems. Chapter 2 introduces the reader to basic solid state physics used later in the thesis. In Chapter 3 I discuss the operation of the experimental techniques and apparatus, including millimetre-wave techniques. In addition, Chapter 3 contains a description of the design of the FTR rotating cavity insert which is unique of its kind. In Chapter 4 a model of oscillating real-space velocity vectors is presented. The model is used to explain the origin of the FTRs observed in the high-frequency magneto- conductivity data. In Chapter 5 I report two studies of the angle dependence of FTRs in the high-frequency magneto-conductivity. The FTRs in {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2} and {alpha}-(BEDT- TTF){sub 2}KHg(SCN){sub 4} show two previously unknown corrugations in the Q1D Fermi-surface sections of the two materials. The FTRs in {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} are investigated both in the density-wave state and near its collapse into a high-temperature, high-field state. In Chapter 6 a study of the

  2. Determining the quantum-coherent to semiclassical transition in atomic-scale quasi-one-dimensional metals

    Science.gov (United States)

    Weber, Bent; Simmons, Michelle Y.

    2016-08-01

    Atomic-scale silicon wires, patterned by scanning tunneling microscopy (STM) and degenerately doped with phosphorus (P), have attracted significant interest owing to their exceptionally low resistivity and semiclassical Ohmic conduction at temperatures as low as T =4.2 K . Here, we investigate the transition from semiclassical diffusive to quantum-coherent conduction in a 4.6 nm wide wire as we decrease the measurement temperature. By analyzing the temperature dependence of universal conductance fluctuations (UCFs) and one-dimensional (1D) weak localization (WL)—fundamental manifestations of quantum-coherent transport in quasi-1D metals—we show that transport evolves from quantum coherent to semiclassical at T ˜4 K . Remarkably, our study confirms that universal concepts of mesoscopic physics such as UCF and 1D WL retain their validity in quasi-1D metallic conductors down to the atomic scale.

  3. NMR study of quasi-one-dimensional itinerant-electron magnets RMn4Al8 ( R=Y, Lu and Sc)

    Science.gov (United States)

    Muro, Y.; Nakamura, H.; Kohara, T.

    2008-04-01

    55Mn-NMR measurements, which revealed previously the presence of spin pseudogap in YMn 4Al 8, have been extended to LuMn 4Al 8 and ScMn 4Al 8. Temperature ( T) dependences of the Knight shift, K, and the nuclear spin-lattice relaxation rate, 1/T1, are well explained by the same pseudogap model used to explain a broad maximum observed in the T-dependence of the susceptibility, indicating common nature in the spin excitation spectrum in the quasi-one-dimensional itinerant-electron compounds.

  4. Phase fluctuations in two coaxial quasi-one-dimensional superconducting cylindrical surfaces serving as a model system for superconducting nanowire bundles

    Science.gov (United States)

    Wong, C. H.; Wu, R. P. H.; Lortz, R.

    2017-03-01

    The dimensional crossover from a 1D fluctuating state at high temperatures to a 3D phase coherent state in the low temperature regime in two coaxial weakly-coupled cylindrical surfaces formed by two-dimensional arrays of parallel nanowires is studied via an 8-state 3D-XY model. This system serves as a model for quasi-one-dimensional superconductors in the form of bundles of weakly-coupled superconducting nanowires. A periodic variation of the dimensional crossover temperature TDC is observed when the inner superconducting cylindrical surface is rotated in the angular plane. TDC reaches a maximum when the relative angle between the cylinders is 2.81°, which corresponds to the maximum separation of nanowires between the two cylindrical surfaces. We demonstrate that the relative strength of phase fluctuations in this system is controllable by the rotational angle between the two surfaces with a strong suppression of the fluctuation strength at 2.81°. The phase fluctuations are suppressed gradually upon cooling, before they abruptly vanish below TDC. Our model thus allows us to study how phase fluctuations can be suppressed in quasi-one-dimensional superconductors in order to achieve a global phase coherent state throughout the nanowire array with zero electric resistance.

  5. Phase fluctuations in two coaxial quasi-one-dimensional superconducting cylindrical surfaces serving as a model system for superconducting nanowire bundles

    Energy Technology Data Exchange (ETDEWEB)

    Wong, C.H., E-mail: ch.kh.vong@urfu.ru [Institute of Physics and Technology, Ural Federal University, Clear Water Bay, Kowloon (Russian Federation); Wu, R.P.H., E-mail: pak-hong-raymond.wu@connect.polyu.hk [Department of Applied Physics, The Hong Kong Polytechnic University (Hong Kong); Lortz, R., E-mail: lortz@ust.hk [Department of Physics, Hong Kong University of Science and Technology (Hong Kong)

    2017-03-15

    The dimensional crossover from a 1D fluctuating state at high temperatures to a 3D phase coherent state in the low temperature regime in two coaxial weakly-coupled cylindrical surfaces formed by two-dimensional arrays of parallel nanowires is studied via an 8-state 3D-XY model. This system serves as a model for quasi-one-dimensional superconductors in the form of bundles of weakly-coupled superconducting nanowires. A periodic variation of the dimensional crossover temperature T{sub DC} is observed when the inner superconducting cylindrical surface is rotated in the angular plane. T{sub DC} reaches a maximum when the relative angle between the cylinders is 2.81°, which corresponds to the maximum separation of nanowires between the two cylindrical surfaces. We demonstrate that the relative strength of phase fluctuations in this system is controllable by the rotational angle between the two surfaces with a strong suppression of the fluctuation strength at 2.81°. The phase fluctuations are suppressed gradually upon cooling, before they abruptly vanish below T{sub DC}. Our model thus allows us to study how phase fluctuations can be suppressed in quasi-one-dimensional superconductors in order to achieve a global phase coherent state throughout the nanowire array with zero electric resistance.

  6. Recent progress in high-pressure studies on organic conductors

    Directory of Open Access Journals (Sweden)

    Syuma Yasuzuka and Keizo Murata

    2009-01-01

    Full Text Available Recent high-pressure studies of organic conductors and superconductors are reviewed. The discovery of the highest Tc superconductivity among organics under high pressure has triggered the further progress of the high-pressure research. Owing to this finding, various organic conductors with the strong electron correlation were investigated under high pressures. This review includes the pressure techniques using the cubic anvil apparatus, as well as high-pressure studies of the organic conductors up to 10 GPa showing extraordinary temperature and pressure dependent transport phenomena.

  7. Organic Conductors: Evidence for Correlation Effects in Infrared Properties

    DEFF Research Database (Denmark)

    Jacobsen, Claus Schelde; Johannsen, Ib; Bechgaard, Klaus

    1984-01-01

    The infrared conductivities of four organic conductors with partially filled one-electron bands are compared. The behavior ranges from near Drude type in the best metal to semiconductorlike in the moderate conductor. Electron-molecular-vibration coupling effects of varying degree are seen in all...

  8. Band dependence of charge density wave in quasi-one-dimensional Ta2NiSe7 probed by orbital magnetoresistance

    Science.gov (United States)

    He, Jiaming; Zhang, Yiran; Wen, Libin; Yang, Yusen; Liu, Jinyu; Wu, Yueshen; Lian, Hailong; Xing, Hui; Wang, Shun; Mao, Zhiqiang; Liu, Ying

    2017-07-01

    Ta2NiSe7 is a quasi-one-dimensional (quasi-1D) transition-metal chalcogenide with Ta and Ni chain structures. An incommensurate charge-density wave (CDW) in this quasi-1D structure was well studied previously using tunnelling spectrum, X-ray, and electron diffraction, whereas its transport property and the relation to the underlying electronic states remain to be explored. Here, we report our results of the magnetoresistance (MR) on Ta2NiSe7. A breakdown of Kohler's rule is found upon entering the CDW state. Concomitantly, a clear change in curvature in the field dependence of MR is observed. We show that the curvature change is well described by the two-band orbital MR, with the hole density being strongly suppressed in the CDW state, indicating that the p orbitals from Se atoms dominate the change in transport through CDW transition.

  9. Paramagnetic anisotropy and spin-flop transition in single crystals of the quasi-one-dimensional system β-Cu2V2O7

    Science.gov (United States)

    He, Zhangzhen; Ueda, Yutaka

    2008-02-01

    Magnetic behaviors of β-Cu2V2O7 single crystals are investigated by means of magnetic susceptibility, magnetization, and heat capacity measurements. Our experimental results show that β-Cu2V2O7 is a quasi-one-dimensional antiferromagnet with Néel temperature of ˜26K . The intrachain and interchain exchanges are estimated to be J∥=39K and J⊥=13.8K , respectively. Also, paramagnetic anisotropy is observed in the system, while a typical spin-flop transition is observed with magnetic field applied along the c axis. Magnetic anisotropy energy at 5K is estimated to be K=6.05(5)×105ergs/cm3 . Spins of Cu2+ ions are suggested to arrange parallel to the c axis and perpendicular to the chains.

  10. The magnetic properties of S={1}/{2} quasi-one-dimensional-quantum spin system DMACuCl3 in magnetic fields

    Science.gov (United States)

    Wada, Osamu; Yoshida, Yasuo; Inagaki, Yuji; Asano, Takayuki; Kawae, Tatsuya; Takeda, Kazuyoshi; Ajiro, Yoshitami

    Magnetic susceptibility χ(T) of a quasi-one-dimensional S={1}/{2} quantum spin system DMACuCl3 (DMA=(CH 3) 2NH 2) has been measured in a magnetic field. This compound exhibits a unique magnetization curve M(H). M(H) rises with increasing magnetic field up to H=2 T, and shows a {1}/{2} plateau between H and H=3.5 T followed by a gradual increase to the saturation at Hs=14 T. In the previous studies, the specific heat C(T) shows a sharp peak in the low field region for H⩽H and in the high field region for H⩽H [Y. Yoshida, O. Wada, Y. Inagaki, T. Asano, K. Takeo, T. Kawae, K. Takeda, Y. Ajiro, J. Phys. Soc. Japan 74 (2005) 2917. [1

  11. LETTER TO THE EDITOR: Unique Fermi surfaces with quasi-one-dimensional character in CeRh3B2 and LaRh3B2

    Science.gov (United States)

    Okubo, T.; Yamada, M.; Thamizhavel, A.; Kirita, S.; Inada, Y.; Settai, R.; Harima, H.; Takegahara, K.; Galatanu, A.; Yamamoto, E.; Onuki, Y.

    2003-11-01

    We have carried out de Haas-van Alphen (dHvA) experiments on a ferromagnet CeRh3B2 with an extremely high Curie temperature T_{\\mathrm {C}} \\simeq 120 K and a non-4f reference compound LaRh3B2. The dHvA data of LaRh3B2 are well explained by the results of energy band calculations. The topology of the Fermi surfaces in CeRh3B2 is found to be very similar to that of LaRh3B2, possessing wavy but flat Fermi surfaces in the basal plane. Observation of a quasi-one-dimensional electronic state is the first such case in a rare earth compound.

  12. Anisotropy in conductance of a quasi-one-dimensional metallic surface state measured by a square micro-four-point probe method.

    Science.gov (United States)

    Kanagawa, Taizo; Hobara, Rei; Matsuda, Iwao; Tanikawa, Takehiro; Natori, Akiko; Hasegawa, Shuji

    2003-07-18

    We have devised a "square micro-four-point probe method" using an independently driven ultrahigh-vacuum four-tip scanning tunneling microscope, and succeeded for the first time to directly measure anisotropic electrical conductance of a single-atomic layer on a solid surface. A quasi-one-dimensional metal of a single-domain Si(111)4 x 1-In had a surface-state conductance along the metallic atom chains (sigma(axially)) to be 7.2(+/-0.6) x 10(-4) S/square at room temperature, which was larger than that in the perpendicular direction (sigma(radially)) by approximately 60 times. The sigma(axially) was consistently interpreted by a Boltzmann equation with the anisotropic surface-state band dispersion, while the sigma(radially) was dominated by a surface-space-charge-layer conductance.

  13. Role of ion beam excitations on quasi one-dimensional magnetic system of Mn-doped LiCuVO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Abhishek [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Dwivedi, G.D.; Kumar, Shiv [Departments of Physics, Banaras Hindu University, Varanasi 221005 (India); Shahi, P.; Shukla, K.K. [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Ghosh, A.K. [Departments of Physics, Banaras Hindu University, Varanasi 221005 (India); Asokan, K.; Kanjilal, D. [Inter University Accelerator Center, ArunaAsaf Ali Marg, New Delhi 110067 (India); Singh, R.K. [Departments of Physics, Banaras Hindu University, Varanasi 221005 (India); Nigam, A.K. [Department of CMP & MS, Tata Institute of Fundamental Research, Mumbai 400 005 (India); Chatterjee, Sandip, E-mail: schatterji.app@iitbhu.ac.in [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2015-07-01

    Induction of short range ferromagnetic ordering has been observed in the quasi one dimensional antiferromagnetic LiCuVO{sub 4} system with doping of Mn in the octahedral (Cu) site. Though, magnetic ordering is not stable enough as further increase of Mn-concentration, magnetic ordering gets deteriorated. This might be the case that Mn{sup 2+} ions, with strong magnetic moment as compared to Cu{sup 2+} ions, enhance the ferromagnetic coupling between the nearest neighbor atoms of quasi-one-dimensional magnetic LiCuVO{sub 4} system. Ferromagnetic ordering in LiCu{sub 0.95}Mn{sub 0.05}VO{sub 4} system also degraded after high energy ion beam excitation which creates defects and may disturb the short range ferromagnetic ordering in its near locality but it does not have much effect on the long range antiferromagnetic ordering. Irradiation causes no change in Raman modes of LiCu{sub 0.95}Mn{sub 0.05}VO{sub 4} system, while it produces some new vibrational modes in intermediate and high frequency region of LiCu{sub 0.9}Mn{sub 0.1}VO{sub 4} system. Above results have been understood based on competitions between ferromagnetic nearest neighbor (NN) coupling and antiferromagnetic next nearest neighbor (NNN) coupling in CuO{sub 2} chain. - Highlights: • Quasi 1-D magnetic systems LiCu{sub 1-x}Mn{sub x}VO{sub 4} (x = 0.00, 0.05 & 0.10) have been prepared. • Doping of Mn induces short range ferromagnetic ordering in the system. • High-energy ion beam excitations degrade ferromagnetic ordering in Mn doped LiCuVO{sub 4}. • Irradiations decay short range FM order but has no effect on long range AFM order. • Irradiation leads to few new vibrational modes in LiCu{sub 0.9}Mn{sub 0.1}VO{sub 4} system.

  14. Charge fluctuations and nodeless superconductivity in quasi-one-dimensional Ta4Pd3Te16 revealed by 125Te-NMR and 181Ta-NQR

    Science.gov (United States)

    Li, Z.; Jiao, W. H.; Cao, G. H.; Zheng, Guo-qing

    2016-11-01

    We report 125Te nuclear magnetic resonance and 181Ta nuclear quadrupole resonance studies on single-crystal Ta4Pd3Te16 , which has a quasi-one-dimensional structure and superconducts below Tc=4.3 K. 181Ta with spin I =7 /2 is sensitive to quadrupole interactions, while 125Te with spin I =1 /2 can only relax by magnetic interactions. By comparing the spin-lattice relaxation rate (1 /T1 ) of 181Ta and 125Te, we found that electric-field-gradient (EFG) fluctuations develop below 80 K. The EFG fluctuations are enhanced with decreasing temperature due to the fluctuations of a charge density wave that sets in at TCDW=20 K, below which the spectra are broadened and 1 /T1T drops sharply. In the superconducting state, 1 /T1 shows a Hebel-Slichter coherence peak just below Tc for 125Te, indicating that Ta4Pd3Te16 is a full-gap superconductor without nodes in the gap function. The coherence peak is absent in the 1 /T1 of 181Ta due to the strong EFG fluctuations.

  15. Quasi-one-dimensional hopping conductivity of the spin-ladder CaCu2O3 single crystals: Influence of the cation and oxygen nonstoichiometry

    Science.gov (United States)

    Lisunov, K. G.; Wizent, N.; Waske, A.; Werner, J.; Tristan, N.; Sekar, C.; Krabbes, G.; Behr, G.; Arushanov, E.; Büchner, B.

    2008-06-01

    The resistivity ρ(T) of the spin-ladder compound CaCu2O3 measured along the Cu-O-Cu leg (j ∥b) exhibits a strongly activated character. It increases from ˜104 to ˜109 Ωm if T decreases from 350 to 100 K. The charge transfer above T ˜200 K is governed by a quasi-one-dimensional (1D) nearest-neighbor hopping (NNH) conductivity mechanism characterized by the law ρ(T )˜exp(Ea/kT). Below 200 K a novel quasi-1D variable-range hopping (VRH) conductivity law ρ(T )˜exp[(T0/T)3/4] is observed, predicted recently by Fogler, Teber, and Shklovskii [Phys. Rev. B 69, 035413 (2004)]. The NNH activation energy Ea and the VRH characteristic temperature T0 exhibit high sensitivity to the cation (Ca, Cu) content, decreasing by 2.3-2.5 times and by 3.0-3.2 times, respectively, when the composition of Ca is changed from 0.854 to 0.786-0.798 and the composition of Cu from 2.039 to 2.159-2.163. The behavior of Ea and T0 can be attributed to a corresponding variation of the concentration of intrinsic defects associated with Cu vacancies. On the other hand, no direct dependence of Ea and T0 to the excess oxygen concentration is observed.

  16. Hydrothermal fabrication of quasi-one-dimensional single-crystalline anatase TiO2 nanostructures on FTO glass and their applications in dye-sensitized solar cells.

    Science.gov (United States)

    Liao, Jin-Yun; Lei, Bing-Xin; Wang, Yu-Fen; Liu, Jun-Min; Su, Cheng-Yong; Kuang, Dai-Bin

    2011-01-24

    One-dimensional and quasi-one-dimensional semiconductor nanostructures are desirable for dye-sensitized solar cells (DSSCs), since they can provide direct pathways for the rapid collection of photogenerated electrons, which could improve the photovoltaic performance of the device. Quasi-1D single-crystalline anatase TiO(2) nanostructures have been successfully prepared on transparent, conductive fluorine-doped tin oxide (FTO) glass with a growth direction of [101] through a facile hydrothermal approach. The influences of the initial titanium n-butoxide (TBT) concentration, hydrothermal reaction temperature, and time on the length of quasi-1D anatase TiO(2) nanostructures and on the photovoltaic performance of DSSCs have been investigated in detail. A power conversion efficiency of 5.81% has been obtained based on the prepared TiO(2) nanostructure photoelectrode 6.7 μm thick and commercial N719 dye, with a short-circuit current density of 13.3 mA cm(-2) , an open-circuit voltage of 810 mV, and a fill factor of 0.54. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. On the control parameters of the quasi-one dimensional superconductivity in Sc{sub 3}CoC{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Eickerling, Georg; Hauf, Christoph; Scheidt, Ernst-Wilhelm; Reichardt, Lena; Schneider, Christian; Scherer, Wolfgang [Institut fuer Physik, Universitaet Augsburg, Universitaetstrasse 1, 86179 Augsburg (Germany); Munoz, Alfonso [Departamento de Fisica Fundamental II, Instituto de Materiales y Nanotecnologia, Universidad de La Laguna, Tenerife (Spain); Lopez-Moreno, Sinhue [Escuela Superior Cd. Sahagun, Universidad Autonoma del Estado de Hidalgo, Carretera Cd. Sahagun-Otumba s/n. 43990, Hidalgo (Mexico); Humberto Romero, Aldo [Physics Department, West Virginia University, Morgantown, West Virginia 26506-6315 (United States); Max Planck Institut fuer Mikrostruktur Physik, Weinberg 2, 06120 Halle (Germany); Porcher, Florence; Andre, Gilles [Laboratoire Leon Brillouin, UMR12 CEA-CNRS, Bat 563 CEA Saclay, 91191 Gif sur Yvette Cedex (France); Poettgen, Rainer [Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster, Corrensstrasse 30, 48149 Muenster (Germany)

    2013-09-15

    Within the series of ternary rare-earth transition metal carbides Sc{sub 3}TC{sub 4} (T = Fe, Co, Ni) only the Co congener displays a structural phase transition at 72 K and an onset of bulk superconductivity at 4.5 K. In this paper we present the results of a detailed analysis of the structural, electronic, and vibrational properties of the low-temperature phase of Sc{sub 3}CoC{sub 4} that represents one of the few well-documented examples of a quasi one-dimensional (1D) superconductor. Variable temperature neutron powder diffraction and low temperature X-ray diffraction experiments were performed in order to confirm the subtle structural distortions during the phase transition. The results of periodic electronic structure calculations indicate, that the structural transition can clearly be identified as a Peierls-type distortion and by a comparison with the isostructural carbide Sc{sub 3}FeC{sub 4} we are able to identify the chemical, electronic, and the vibrational control parameters of the transition. Topological analyses of the electron density distribution and of the valence shell charge concentrations at the cobalt atom finally allow us to directly correlate the changes in the electronic structure due to the Peierls transition in reciprocal space with the according subtle changes in the real space properties of Sc{sub 3}CoC{sub 4}. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Quasi-linear magnetoresistance and the violation of Kohler's rule in the quasi-one-dimensional Ta₄Pd₃Te₁₆ superconductor.

    Science.gov (United States)

    Xu, Xiaofeng; Jiao, W H; Zhou, N; Guo, Y; Li, Y K; Dai, Jianhui; Lin, Z Q; Liu, Y J; Zhu, Zengwei; Lu, Xin; Yuan, H Q; Cao, Guanghan

    2015-08-26

    We report on the quasi-linear in field intrachain magnetoresistance in the normal state of a quasi-one-dimensional superconductor Ta4Pd3Te16 (Tc ~ 4.6 K). Both the longitudinal and transverse in-chain magnetoresistance shows a power-law dependence, Δρ∝B(α) with the exponent α close to 1 over a wide temperature and field range. The magnetoresistance shows no sign of saturation up to 50 T studied. The linear magnetoresistance observed in Ta4Pd3Te16 is found to be overall inconsistent with the interpretations based on the Dirac fermions in the quantum limit, charge conductivity fluctuations as well as quantum electron-electron interference. Moreover, it is observed that the Kohler's rule, regardless of the field orientations, is violated in its normal state. This result suggests the loss of charge carriers in the normal state of this chain-containing compound, due presumably to the charge-density-wave fluctuations.

  19. 1D to 3D dimensional crossover in the superconducting transition of the quasi-one-dimensional carbide superconductor Sc3CoC4.

    Science.gov (United States)

    He, Mingquan; Wong, Chi Ho; Shi, Dian; Tse, Pok Lam; Scheidt, Ernst-Wilhelm; Eickerling, Georg; Scherer, Wolfgang; Sheng, Ping; Lortz, Rolf

    2015-02-25

    The transition metal carbide superconductor Sc(3)CoC(4) may represent a new benchmark system of quasi-one-dimensional (quasi-1D) superconducting behavior. We investigate the superconducting transition of a high-quality single crystalline sample by electrical transport experiments. Our data show that the superconductor goes through a complex dimensional crossover below the onset T(c) of 4.5 K. First, a quasi-1D fluctuating superconducting state with finite resistance forms in the [CoC(4)](∞) ribbons which are embedded in a Sc matrix in this material. At lower temperature, the transversal Josephson or proximity coupling of neighboring ribbons establishes a 3D bulk superconducting state. This dimensional crossover is very similar to Tl(2)Mo(6)Se(6), which for a long time has been regarded as the most appropriate model system of a quasi-1D superconductor. Sc(3)CoC(4) appears to be even more in the 1D limit than Tl(2)Mo(6)Se(6).

  20. Magnetic interactions in a quasi-one-dimensional antiferromagnet Cu(H{sub 2}O){sub 2}(en)SO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Sýkora, Rudolf, E-mail: rudolf.sykora@vsb.cz; Legut, Dominik [Nanotechnology Centre, VSB–Technical University of Ostrava, Ostrava 70833 (Czech Republic)

    2014-05-07

    A theoretical ab-initio investigation of exchange interaction between Cu atoms in an insulating antiferromagnet Cu(H{sub 2}O){sub 2}(en)SO{sub 4}, en = C{sub 2}H{sub 8}N{sub 2}, is reported. While the previous experimental studies described the system's magnetism to be quasi-two-dimensional, our results, based on a mapping of the system onto an effective Heisenberg model, rather support a quasi-one-dimensional character with the exchange coupling between the Cu atoms being propagated mainly along a zigzag line lying in the crystal's bc plane and connecting the Cu atoms through the N atoms. Further, the direction of magnetic moments on the Cu atoms is suggested to be nearly along the crystal's a axis. A check of the change in the exchange constants induced either by external pressure or by various values of U in the GGA + U approximation is made. Finally, based on experimental values of positions of broad maxima in magnetic-susceptibility and specific-heat curves and using theoretical expressions available in the literature a relevant value of the U parameter and related expected value of the electronic gap are estimated to be about 5 eV and 2 eV, respectively.

  1. 133Cs and 75As NMR investigation of the normal metallic state of quasi-one-dimensional Cs2Cr3As3

    Science.gov (United States)

    Zhi, Haizhao; Lee, Drake; Imai, Takashi; Tang, Zhangtu; Liu, Yi; Cao, Guanghan

    2016-05-01

    We report 133Cs NMR and 75As nuclear quadrupole resonance (NQR) measurements on the normal metallic state above Tc of a quasi-one-dimensional superconductor Cs2Cr3As3 (Tc<1.6 K). From the 133Cs NMR Knight shift 133K measured at the Cs1 site, we show that the uniform spin susceptibility χspin increases from 295 K to ˜60 K, followed by a mild suppression; χspin then levels off below ˜10 K. In contrast, a vanishingly small magnitude of 133K indicates that Cs2 sites contribute very little to electrical conduction and the exchange interactions between 3d electrons at Cr sites. Low frequency Cr spin dynamics, reflected on 75As1 /T1T (the nuclear spin-lattice relaxation rate 1 /T1 divided by temperature T ), shows an analogous trend as χspin. Comparison with the results of 1 /T1T near Tc with K2Cr3As3 (Tc=6.1 K) and Rb2Cr3As3 (Tc=4.8 K) establishes a systematic trend that substitution of K+ ions with larger alkali ions progressively suppresses Cr spin fluctuations together with Tc.

  2. Effects of a dimple potential on the ground-state properties of a quasi-one-dimensional Bose–Einstein condensate with two- and three-body interactions

    Energy Technology Data Exchange (ETDEWEB)

    Karabulut, Elife Ö.

    2015-04-01

    The ground state of a quasi-one-dimensional interacting Bose gas confined by a harmonic plus Gaussian dimple potential is studied within the variational approach and also Gross–Pitaevskii mean-field approximation. The effect of the superimposed dimple trap on the order parameter, the chemical and effective potentials of the system is analyzed for repulsive and attractive two- as well as three-body interactions between the particles. The results obtained from both methods show that the characteristics of the trap such as the width and depth of the dimple affect the corresponding ground state properties of the system in a qualitatively similar way to the repulsive and attractive interatomic interactions, respectively. - Highlights: • We study the effects of a dimple potential on a quasi-1D Bose-Einstein condensate. • We used variational and Gross-Pitaevskii mean-field approaches. • The width of the dimple affects the system similarly to repulsive interaction. • The depth of the dimple affects the system similarly to attractive interaction.

  3. Facile Synthesis of Quasi-One-Dimensional Au/PtAu Heterojunction Nanotubes and Their Application as Catalysts in an Oxygen-Reduction Reaction.

    Science.gov (United States)

    Cai, Kai; Liu, Jiawei; Zhang, Huan; Huang, Zhao; Lu, Zhicheng; Foda, Mohamed F; Li, Tingting; Han, Heyou

    2015-05-11

    An intermediate-template-directed method has been developed for the synthesis of quasi-one-dimensional Au/PtAu heterojunction nanotubes by the heterogeneous nucleation and growth of Au on Te/Pt core-shell nanostructures in aqueous solution. The synthesized porous Au/PtAu bimetallic nanotubes (PABNTs) consist of porous tubular framework and attached Au nanoparticles (AuNPs). The reaction intermediates played an important role in the preparation, which fabricated the framework and provided a localized reducing agent for the reduction of the Au and Pt precursors. The Pt7 Au PABNTs showed higher electrocatalytic activity and durability in the oxygen-reduction reaction (ORR) in 0.1 M HClO4 than porous Pt nanotubes (PtNTs) and commercially available Pt/C. The mass activity of PABNTs was 218 % that of commercial Pt/C after an accelerated durability test. This study demonstrates the potential of PABNTs as highly efficient electrocatalysts. In addition, this method provides a facile strategy for the synthesis of desirable hetero-nanostructures with controlled size and shape by utilizing an intermediate template. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. The temperature dependent shear strain of the (NbSe4)(10)I-3 compound, a quasi-one-dimensional charge density wave system, below the Peierls transition

    NARCIS (Netherlands)

    Vucic, Z; Gladic, J; Haas, C; DeBoer, JL

    1996-01-01

    An X-ray study of the quasi-one-dimensional charge density wave (CDW) system (NbSe4)(10)I-3 as a function of temperature from room temperature down to 130 K has been performed by taking oscillation and zeroth level Weissenberg photographs. A reversible transformation of the room temperature tetragon

  5. Quasi-one-dimensional nanostructured cobalt (Co) intercalated vanadium oxide (V{sub 2}O{sub 5}): Peroxovanadate sol gel synthesis and structural study

    Energy Technology Data Exchange (ETDEWEB)

    Langie da Silva, Douglas, E-mail: douglas.langie@ufpel.edu.br [Departamento de Física, Universidade Federal de Pelotas, Caixa Postal 354, Pelotas 96010-900 (Brazil); Moreira, Eduardo Ceretta [Laboratório de Espectroscopia, Universidade Federal do Pampa, Campus Bagé, Bagé 96400-970 (Brazil); Dias, Fábio Teixeira; Neves Vieira, Valdemar das [Departamento de Física, Universidade Federal de Pelotas, Caixa Postal 354, Pelotas 96010-900 (Brazil); Brandt, Iuri Stefani; Cas Viegas, Alexandre da; Pasa, André Avelino [Laboratório de Filmes Finos e Superfícies, Universidade Federal de Santa Catarina, Caixa Postal 476, Florianópolis 88.040-900 (Brazil)

    2015-01-15

    Nanostructured cobalt vanadium oxide (V{sub 2}O{sub 5}) xerogels spread onto crystalline Si substrates were synthesized via peroxovanadate sol gel route. The resulting products were characterized by distinct experimental techniques. The surface morphology and the nanostructure of xerogels correlate with Co concentration. The decrease of the structural coherence length is followed by the formation of a loose network of nanopores when the concentration of intercalated species was greater than 4 at% of Co. The efficiency of the synthesis route also drops with the increase of Co concentration. The interaction between the Co(OH{sub 2}){sub 6}{sup 2+} cations and the (H{sub 2}V{sub 10}O{sub 28}){sup 4−} anions during the synthesis was suggested as a possible explanation for the incomplete condensation of the V{sub 2}O{sub 5} gel. Finally the experimental results points for the intercalation of Co between the bilayers of the V{sub 2}O{sub 5}. In this scenario two possible preferential occupation sites for the metallic atoms in the framework of the xerogel were proposed. - Graphical abstract: Quasi-one-dimensional nanostructured cobalt (Co) intercalated vanadium oxide (V{sub 2}O{sub 5}) nanoribbons synthesized by peroxovanadate sol gel route. - Highlights: • Nanostructured cobalt V{sub 2}O{sub 5} gel spread onto c{sub S}i were synthesized via peroxovanadate sol gel route. • The micro and nanostructure correlates with the cobalt content. • The efficiency of the synthesis route shows to be also dependent of Co content. • The experimental results points for the intercalation of Co between the bilayers of the V{sub 2}O{sub 5} xerogel.

  6. The metallic transport of (TMTSF){sub 2}X organic conductors close to the superconducting phase

    Energy Technology Data Exchange (ETDEWEB)

    Auban-Senzier, P; Jerome, D [Laboratoire de Physique des Solides, UMR 8502 CNRS Universite Paris-Sud, 91405 Orsay (France); Doiron-Leyraud, N; Rene de Cotret, S; Sedeki, A; Bourbonnais, C; Taillefer, L [Departement de Physique and RQMP, Universite de Sherbrooke, Sherbrooke, QC, J1K 2R1 (Canada); Alemany, P [Departament de Quimica Fisica and Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Canadell, E [Institut de Ciencia de Materials de Barcelona (CSIC), Campus de la UAB, 08193 Bellaterra (Spain); Bechgaard, K, E-mail: pascale.senzier@lps.u-psud.fr, E-mail: denis.jerome@lps.u-psud.fr, E-mail: ndl@physique.usherbrooke.ca, E-mail: cbourbon@physique.usherbrooke.ca, E-mail: ltaillef@physique.usherbrooke.ca, E-mail: p.alemany@ub.edu, E-mail: canadell@icmab.es [Department of Chemistry, HC Oersted Institute, Copenhagen (Denmark)

    2011-08-31

    Comparing resistivity data of the quasi-one-dimensional superconductors (TMTSF){sub 2}PF{sub 6} and (TMTSF){sub 2}ClO{sub 4} along the least conducting c*-axis and along the high conductivity a-axis as a function of temperature and pressure, a low temperature regime is observed in which a unique scattering time governs the transport along both directions of these anisotropic conductors. However, the pressure dependence of the anisotropy implies a large pressure dependence of the interlayer coupling. This is in agreement with the results of first-principles density functional theory calculations implying methyl group hyperconjugation in the TMTSF molecule. In this low temperature regime, both materials exhibit for {rho}{sub c} a temperature dependence aT + bT{sup 2}. Taking into account the strong pressure dependence of the anisotropy, the T-linear {rho}{sub c} is found to correlate with the suppression of the superconducting T{sub c}, in close analogy with {rho}{sub a} data. This work reveals the domain of existence of the three-dimensional coherent regime in the generic (TMTSF){sub 2}X phase diagram and provides further support for the correlation between T-linear resistivity and superconductivity in non-conventional superconductors. (paper)

  7. Non-equilibrium and band tailing in organic conductors

    Indian Academy of Sciences (India)

    A T Oza; P C Vinodkumar; R G Patel

    2003-03-01

    The concept of band tailing with focal point and width of the tail from IR absorption spectra of different organic conductors is found valid even for thermal and elastic changes. The experimental situations like change of solvents, method of preparation, applied pressure and pressure cycle apart from compositions is analyzed within the framework of tailing of states. Non-equilibrium due to coupling between applied energy and free electrons can be responsible for the exponential relaxation from non-equilibrium to equilibrium.

  8. Study on Magnetic Properties of Quasi-one-dimensional Organic Ferromagnet%准一维有机铁磁体的磁学性质研究

    Institute of Scientific and Technical Information of China (English)

    贺泽东; 揭泉林; 罗时军

    2010-01-01

    基于Heisenberg模型,利用Monte Carlo方法研究准一维有机铁磁体在不同温度,不同外磁场下的磁学性质.结果显示:自由基与主链间的反铁磁相互作用越强,相变温度越高;二聚化则削弱系统的磁性;而自由基之间的耦合增强系统的铁磁性,并提高居里温度;磁化强度曲线在低温下表现出1/3磁化强度平台,并以三个临界磁场为特征.

  9. Determination of the Fermi velocity by angle-dependent periodic orbit resonance measurements in the organic conductor α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Kovalev, A. E.; Hill, S.; Qualls, J. S.

    2002-10-01

    We report on detailed angle-dependent studies of the microwave (ν=50-90 GHz) interlayer magnetoelectrodynamics of a single crystal sample of the organic charge-density-wave (CDW) conductor α-(BEDT-TTF)2KHg(SCN)4. Recently developed instrumentation enables both magnetic-field (B) sweeps for a fixed sample orientation and angle sweeps at fixed ν/B. We observe series' of resonant absorptions, which we attribute to periodic orbit resonances (POR)-a phenomenon closely related to cyclotron resonance. The angle dependence of the POR indicates that they are associated with the low-temperature quasi-one-dimensional (Q1D) Fermi surface (FS) of the title compound; indeed, all of the resonance peaks collapse onto a single set of ν/B versus angle curves, generated using a semiclassical magnetotransport theory for a single Q1D FS. We show that Q1D POR measurements provide one of the most direct methods for determining the Fermi velocity, without any detailed assumptions concerning the band structure; our analysis yields an average value of vF=6.5×104 m/s. Quantitative analysis of the POR harmonic content indicates that the Q1D FS is strongly corrugated. This is consistent with the assumption that the low-temperature FS derives from a reconstruction of the high-temperature quasi-two-dimensional FS, caused by the CDW instability. Detailed analysis of the angle dependence of the POR yields parameters associated with the CDW superstructure, which are consistent with published results. Finally, we address the issue as to whether or not the interlayer electrodynamics are coherent in the title compound. We obtain a relaxation time from the POR linewidths, which is considerably longer than the interlayer hopping time, indicating that the transport in this direction is coherent.

  10. 磁流体管流准一维模型的数值验证与性能分析%Validation and Performance Analysis for the Quasi-One-Dimensional Models of MHD Flows

    Institute of Scientific and Technical Information of China (English)

    陈瑞锋; 魏志军; 王宁飞

    2012-01-01

    为了快速分析磁流体管流,采用涡轮喷气发动机模型对磁流体管流进行类比分析,引入变截面管流理论和修改过的多变效率表达式,推导了磁流体发电器和加速器的准一维模型,采用二维数值方法验证了准一维模型的可行性,利用该准一维模型对磁流体管流进行了性能分析,结果表明,多变效率的引入使准一维模型更加完整,当负载系数不变时,磁流体装置中的平均马赫数越低,其等熵效率越高。%For the Purpose of quick analysis for the magnetohydrodynamic (MHD) flow, quasi-one-dimensional models for the MHD equipments have been deduced using the turbojet engine model, the variable cross-section pipe flow theory and the expressions of modified polytropie efficiencies. The feasibility of the quasi-one-dimensional models have been validated with the 2D numerical method. Then, the performance analysis has been performed with these quasi-one-dimensional models, which shows that the modified polytropic efficiencies make the models improved, and when the load factors is kept to be constant, the effieiencies of the MHD flow increase by decreasing the average Mach number.

  11. Optical characterization of 2 kF bond-charge-density wave in quasi-one-dimensional 3 /4 -filled (EDO-TTF)2 X ( X= PF6 and AsF6 )

    Science.gov (United States)

    Drozdova, Olga; Yakushi, Kyuya; Yamamoto, Kaoru; Ota, Akira; Yamochi, Hideki; Saito, Gunzi; Tashiro, Hidenori; Tanner, David B.

    2004-08-01

    We present the electronic and vibrational spectra of quasi-one-dimensional (3)/(4) -filled (EDO-TTF)2X ( EDO-TTF=ethylenedioxy-tetrathiafulvalene , X=PF6 and AsF6 ) above and below the metal-insulator phase transition ( TMI=280K for the PF6 salt and 268K for the AsF6 salt). For the low-temperature insulating phase, the pattern of both bond and charge order was identified. Almost all charge density is localized on the strongly bound central pair of 0110 tetramer giving rise to a characteristic spectrum of electronic excitations. Infrared spectra along the stacking axis show evidence of strong electron-molecular vibration coupling between the charge transfer band within the pair and some specific intramolecular vibrations. This charge order is assisted by a molecular deformation.

  12. Time-dependent Quantum Transport Properties for Quasi-one-dimensional Carbon Nanotube System%准一维碳纳米管的含时输运性质的研究

    Institute of Scientific and Technical Information of China (English)

    夏春萍; 肖广然; 李浩; 王伟

    2013-01-01

    In this paper,a numerical simulation method for studying the time-dependent transport properties of a quasi-one-dimensional carbon nanotube system is provided.Due to the non-equilibrium Green's function(NEGF),this approach effectively calculates the electrical properties of a quasi-one-dimensional carbon nanotube system.In this paper,the results are showed the greater coupling between the electrode and the carbon nanotubes,the steeper initial current rising,and the smaller relaxation time when a continuous square pulse voltage is injected into the lead.When the frequency of input sinusoidal is low,the current curve becomes irregular.The simulation results will be in favor of both evaluating the electrical properties of nano-materials and providing theoretical guidance for design and optimization of the nanoelectronic devices.%提出了一种数值模拟方法,用于研究准一维碳纳米管系统的含时输运特性.基于非平衡格林函数,通过提出的方法,对准一维碳纳米管系统的电学性质进行数值计算.计算结果显示:当同一连续方波作用于电极时,电极与碳纳米管之间的耦合能越大,电流的最初上升值越大,弛豫时间越短;当输入电压为低频正弦信号,响应电流曲线变得不规则.本仿真结果有利于对纳米材料电学性质的评估,为纳米电子器件的设计和优化提供理论指导.

  13. Organic mixed conductors for bioelectronic applications (Conference Presentation)

    Science.gov (United States)

    Rivnay, Jonathan

    2016-09-01

    Direct measurement and stimulation of electrophysiological activity is a staple of neural and cardiac health monitoring, diagnosis and/or therapy. The ability to sensitively detect these signals can be enhanced by organic electronic materials that show mixed conduction properties (both electronic and ionic transport) in order to bridge the inherent mismatch that is prevalent between biological systems and traditional microelectronic materials/devices. Organic electrochemical transistors (OECTs) are one class of devices that utilize organic mixed conductors as the transistor channel, and have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance. These devices are fabricated in flexible, conformable form factors for in vivo recordings of epileptic activity, and for cutaneous EEG and ECG recordings in human subjects. The majority of high performance devices are based on conducting polymers such as poly(3,4-ethylenedioxythiophene) :poly(styrenesulfonate), PEDOT:PSS. By investigating PEDOT-based materials and devices, we are able to construct design rules for new formulations/materials. Introducing glycolated side chains to carefully selected semiconducting polymer backbones has enabled a new class high performance bioelectronic materials that feature high volumetric capacitance, transconductance >10mS (device dimensions ca. 10um), and steep subthreshold switching characteristics. A sub-set of these materials outperform PEDOT:PSS and shows significant promise for low power in vitro and in vivo biosensing applications.

  14. QUASI-ONE DIMENSIONAL CLASSICAL FLUIDS

    Directory of Open Access Journals (Sweden)

    J.K.Percus

    2003-01-01

    Full Text Available We study the equilibrium statistical mechanics of simple fluids in narrow pores. A systematic expansion is made about a one-dimensional limit of this system. It starts with a density functional, constructed from projected densities, which depends upon projected one and two-body potentials. The nature of higher order corrections is discussed.

  15. Effects of gradient disorder on electronic transport in quasi-one-dimensional nanowires%准一维纳米线电子输运的梯度无序效应

    Institute of Scientific and Technical Information of China (English)

    段玲; 胡飞; 丁建文

    2011-01-01

    考虑实际体系的梯度无序和结散射,发展格林函数矩阵分解消元方法,研究了准一维纳米线的电子输运性质.结果表明,由于结散射,电导随能量呈现振荡行为,无序的引入破坏了电子相干性,在低无序度区平均电导呈现异常增加,呈现一个新的电导峰.当表面存在无序但无梯度衰减时,体系的平均电导随无序度增强先减后增,出现类局域—退局域性转变.当表面无序线性衰减时,平均电导在强无序区稍有增加,而当表面无序高斯型衰减时,平均电导指数衰减,类局域—退局域性转变消失,不同于以前的理论预言.研究结果对准一维纳米线电子器件的结构设计和应用有指导作用.%Considering both the gradient decay of the real disorder and the contact scattering,we investigate the electronic transport in quasi-one-dimensional nanowires by developing a decomposition elimination method for Green's function matrix.In the presence the contact scattering,the conductance oscillates with energy.For some energies of incident electrons,an abnormal enhancement is obtained in the average conductance due to the destroyed coherence by the introduction of much low disorder,showing that there appears a new conductance peak.In the absence of disorder gradient,the average conductance firstly decreases then increases with disorder strength,indicating that there exists a localization-delocalization transition.In the presence of linearly decaying disorder,the average conductance increases slightly in a strong disorder region.In the case of the Gaussian-type decaying disorder,the average conductance decreases exponentially and the localization-delocalization transition disappears,which is different from previous thereotical result.The results are helpful for the design and the application of quasi-one-dimensional nanowires device.

  16. Enhanced magnetocaloric effect in quasi-one-dimensional S = 1/2 Heisenberg antiferromagnet [Cu(dmen){sub 2}(H{sub 2}O)]SiF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Orendáč, M., E-mail: martin.orendac@upjs.sk; Čižmár, E.; Orendáčová, A.; Tkáčová, J.; Kuchár, J.; Černák, J.

    2014-02-15

    Highlights: • Low-dimensional magnetic behavior was found in [Cu(dmen){sub 2}(H{sub 2}O)]SiF{sub 6}. • Enhanced magnetocaloric effect occurs at low enough temperatures (T ≪ J/k{sub B}). • The isothermal change of entropy can be 20 times larger than that in paramagnet. -- Abstract: The results of specific heat and electron-spin resonance of [Cu(dmen){sub 2}(H{sub 2}O)]SiF{sub 6} (dmen = N,N-dimethyl-1,2-diaminoethane) are reported. The studied material can be considered as an S = 1/2 quasi-one-dimensional Heisenberg antiferromagnet with dominant intrachain interaction J{sub intra}/k{sub B} = −3.59 K. The appearance of both normal and inverse magnetocaloric effect in various field ranges below saturation field B{sub sat} is tentatively attributed to weaker ferromagnetic interchain interactions. Pronounced magnetocaloric effect is found in the vicinity of B{sub sat,} where at temperatures T ≪ |J{sub intra}/k{sub B}|, the isothermal change of entropy was found to be about 20 times higher than that in S = 1/2 paramagnet. The potential origin of the observed behavior is discussed.

  17. An Organic Mixed Ion–Electron Conductor for Power Electronics

    DEFF Research Database (Denmark)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar

    2016-01-01

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting...

  18. An Organic Mixed Ion-Electron Conductor for Power Electronics

    DEFF Research Database (Denmark)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar

    2016-01-01

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting...

  19. High magnetic field studies of BEDT-TTF organic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Honold, M.M

    1999-07-01

    This Thesis gives a detailed account of the high magnetic field properties of {alpha}-phase BEDT-TTF charge-transfer salts, with particular focus on the salts {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} and {alpha}-(BEDT-TTF){sub 2}TlHg(SCN){sub 4}. The existence of the bulk quantum Hall effect and its eventual destruction in the high-field limit is shown by a variety of experimental means, including magnetoresistance, magnetisation and Hall potential oscillation studies; the latter are based on a new technique specifically developed for this purpose. Chapter 1 introduces the concept of organic conductors and emphasises their potential as prototype systems of reduced dimensionality; in Chapter 2, the necessary physics and experimental techniques for their investigation are outlined. Following model calculations which suggested the possibility of the quantum Hall effect in {alpha}-phase BEDT-TTF salts, measurements of the Hall resistivity were carried out on {alpha}-(BEDT-TTF){sub 2}TlHg(SCN){sub 4} (described in Chapter 3). These exhibit a series of plateaux and represent the direct observation of the quantum Hall effect in a bulk material. Chapter 4 reports the discovery of an anomalous magnetotransport mode in the interplane resistance of {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} which involves the suppression and phase inversion of the Shubnikov-de Haas oscillations at low temperatures. This is interpreted as the action of a two-dimensional chiral Fermi liquid formed from the current-carrying edge states of each quantum Hall layer. Chapter 5 reports the first observation of magnetic breakdown in the high-field phase of {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4}, allowing an improved description of the high-field Fermi surface topology. These results are used to develop a new model for the nested low-field Fermi surface which can explain experimental evidence previously unaccounted for. Studies of the limiting behaviour of Hall potential oscillations in Chapter 6 show

  20. An Organic Mixed Ion-Electron Conductor for Power Electronics.

    Science.gov (United States)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar; Khan, Zia Ullah; Andreasen, Jens W; Liu, Xianjie; Zhao, Dan; Zhang, Hao; Yao, Yulong; Brill, Joseph W; Engquist, Isak; Fahlman, Mats; Wågberg, Lars; Crispin, Xavier; Berggren, Magnus

    2016-02-01

    A mixed ionic-electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio-phene):-poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

  1. Cryogenic separation of hydrogen isotopes in single-walled carbon and boron-nitride nanotubes: insight into the mechanism of equilibrium quantum sieving in quasi-one-dimensional pores.

    Science.gov (United States)

    Kowalczyk, Piotr; Gauden, Piotr A; Terzyk, Artur P

    2008-07-17

    Quasi-one-dimensional cylindrical pores of single-walled boron nitride and carbon nanotubes efficiently differentiate adsorbed hydrogen isotopes at 33 K. Extensive path integral Monte Carlo simulations revealed that the mechanisms of quantum sieving for both types of nanotubes are quantitatively similar; however, the stronger and heterogeneous external solid-fluid potential generated from single-walled boron nitride nanotubes enhanced the selectivity of deuterium over hydrogen both at zero coverage and at finite pressures. We showed that this enhancement of the D(2)/H(2) equilibrium selectivity results from larger localization of hydrogen isotopes in the interior space of single-walled boron nitride nanotubes in comparison to that of equivalent single-walled carbon nanotubes. The operating pressures for efficient quantum sieving of hydrogen isotopes are strongly depending on both the type as well as the size of the nanotube. For all investigated nanotubes, we predicted the occurrence of the minima of the D(2)/H(2) equilibrium selectivity at finite pressure. Moreover, we showed that those well-defined minima are gradually shifted upon increasing of the nanotube pore diameter. We related the nonmonotonic shape of the D(2)/H(2) equilibrium selectivity at finite pressures to the variation of the difference between the average kinetic energy computed from single-component adsorption isotherms of H(2) and D(2). In the interior space of both kinds of nanotubes hydrogen isotopes formed solid-like structures (plastic crystals) at 33 K and 10 Pa with densities above the compressed bulk para-hydrogen at 30 K and 30 MPa.

  2. Spectroscopy of charge transfer complexes of four amino acids as organic two-dimensional conductors

    Energy Technology Data Exchange (ETDEWEB)

    Padhiyar, Ashvin; Patel, A J; Oza, A T [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388 120, Gujarat (India)

    2007-12-05

    It is found in this study that four amino acids, namely asparagine, arginine, histidine and glutamine form two-dimensional conducting systems which are charge transfer complexes (CTCs) with organic acceptors like TCNQ, TCNE, chloranil, DDQ, TNF and iodine. It is verified using optical absorption edges that these are 2d conductors like transition metal dichalcogenides obeying absorption functions different from 1d and 3d conductors. This 2d nature is related to the network of intermolecular H-bonding in these complexes, which leads to a global H-bonded network resulting in the absence of local deformation due to the relaxation of strain.

  3. Spectroscopy of charge transfer complexes of four amino acids as organic two-dimensional conductors

    Science.gov (United States)

    Padhiyar, Ashvin; Patel, A. J.; Oza, A. T.

    2007-12-01

    It is found in this study that four amino acids, namely asparagine, arginine, histidine and glutamine form two-dimensional conducting systems which are charge transfer complexes (CTCs) with organic acceptors like TCNQ, TCNE, chloranil, DDQ, TNF and iodine. It is verified using optical absorption edges that these are 2d conductors like transition metal dichalcogenides obeying absorption functions different from 1d and 3d conductors. This 2d nature is related to the network of intermolecular H-bonding in these complexes, which leads to a global H-bonded network resulting in the absence of local deformation due to the relaxation of strain.

  4. Correlation versus surface effects in photoemission of quasi-1D organic conductors

    DEFF Research Database (Denmark)

    Claessen, R.; Schwingenschlogl, U.; Sing, M.;

    2002-01-01

    The absence of spectral weight at the Fermi level in photoemission spectra of quasi-1D organic conductors has been interpreted as possible evidence for an unusual many-body state. We demonstrate that great care must be exercised to draw this conclusion exclusively on the basis of a pseudogap...

  5. Fast photo-induced phase switching in organic conductor crystal; (EDO-TTF)2PF6

    Science.gov (United States)

    Chollet, Matthieu; Guerin, Laurent; Uchida, Naoki; Fukaya, Souichi; Ishikawa, Tadahiko; Koshihara, Shin-ya; Matsuda, Kazunari; Ota, Akira; Yamochi, Hideki; Saito, Gunzi

    Organic conductor (EDO-TTF) 2PF6 crystal shows metal (M)-insulator (I) transition at 280 K. Here, we report the occurrence of highly efficient photo-conversion from insulator to metal phase within a few pico-seconds.

  6. Control of electronic properties of organic conductors by hydrostatic and uniaxial compression

    Energy Technology Data Exchange (ETDEWEB)

    Kagoshima, S.; Kondo, R.; Hirai, H.; Shibata, T.; Kaga, Y. [Tokyo Univ. (Japan). Dept. of Basic Science; Maesato, M. [Kyoto Univ. (Japan). Dept. of Chemistry

    2001-01-01

    We developed the uniaxial strain method to artificially control the electronic properties of organic conductors by reducing the intermolecular distance along a desired direction without changing those along others. Using this method, we were able to cause and enhance superconductivity in two-dimensional organic conductors, {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} and its isostructural compound having NH{sub 4} instead of K. We found that these two compounds show essentially the same properties if their lattice parameters are appropriately reduced by the uniaxial strain method, although they show quite different properties under ambient and hydrostatic pressures. In the one-dimensional organic superconductor (TMTSF){sub 2}PF{sub 6}, we found a novel result that is contradictory to the current interpretation for the suppression of spin density waves under pressures. (orig.)

  7. Hydrogen bond-promoted metallic state in a purely organic single-component conductor under pressure.

    Science.gov (United States)

    Isono, Takayuki; Kamo, Hiromichi; Ueda, Akira; Takahashi, Kazuyuki; Nakao, Akiko; Kumai, Reiji; Nakao, Hironori; Kobayashi, Kensuke; Murakami, Youichi; Mori, Hatsumi

    2013-01-01

    Purely organic materials are generally insulating. Some charge-carrier generation, however, can provide them with electrical conductivity. In multi-component organic systems, carrier generation by intermolecular charge transfer has given many molecular metals. By contrast, in purely organic single-component systems, metallic states have rarely been realized although some neutral-radical semiconductors have been reported. Here we uncover a new type of purely organic single-component molecular conductor by utilizing strong hydrogen-bonding interactions between tetrathiafulvalene-based electron-donor molecules. These conductors are composed of highly symmetric molecular units constructed by the strong intra-unit hydrogen bond. Moreover, we demonstrate that, in this system, charge carriers are produced by the partial oxidation of the donor molecules and delocalized through the formation of the symmetric intra-unit hydrogen bonds. As a result, our conductors show the highest room-temperature electrical conductivity and the metallic state under the lowest physical pressure among the purely organic single-component systems, to our knowledge.

  8. Gossamer superconductivity near antiferromagnetic Mott insulator in layered organic conductors.

    Science.gov (United States)

    Gan, J Y; Chen, Yan; Su, Z B; Zhang, F C

    2005-02-18

    Layered organic superconductors are on the verge of the Mott insulator. We use the Gutzwiller variational method to study a two-dimensional Hubbard model including a spin exchange coupling term as a minimal model for the compounds. The ground state is found to be a Gossamer superconductor at small on-site Coulomb repulsion U and an antiferromagnetic Mott insulator at large U, separated by a first order phase transition. Our theory is qualitatively consistent with major experiments reported in organic superconductors.

  9. Kinetic phenomena in organic conductors in high magnetic fields (Review Article)

    Science.gov (United States)

    Peschansky, V. G.; Stepanenko, D. I.

    2016-11-01

    A review of experimental and theoretical studies of transport phenomena in strongly anisotropic organic conductors is presented. Considerable attention is paid to the phenomena that are specific to quasi-2D and quasi-1D conductive structures and have no analogues both in ordinary metals and in truly 2D or 1D conducting systems. Angular magnetoresistance oscillations, de Haas-van Alphen and Shubnikov-de Haas phenomena, high-temperature quantum oscillations of the magnetoresistance, and high-frequency resonances, including those arising due to the motion of electrons open trajectories, are discussed. The resonant angular oscillations of high-frequency conductivity and weakly damped electromagnetic waves in quasi-2D organic conductors under strong spatial dispersion are considered.

  10. Toward crystal design in organic conductors and superconductors.

    Energy Technology Data Exchange (ETDEWEB)

    Geiser, U.

    1999-04-23

    We have seen that many different types of intermolecular interactions in organic conducting cation radical salts. Hydrogen bonding between the donor molecules and the anions is weak but not negligible. The ionic Madelung energy is insufficient to completely intersperse anions and cations, thus the layers favored by the van der Waals interactions remain intact. The search for new conducting and superconducting salts has been mainly by trial-and-error methods, even though simple substitutions have been employed in order to obtain isostructural analogs of successful (e.g., superconducting) salts. However, even seemingly minor substitutions sometimes destroy the packing type, and different crystal structures result. Simulations with the aim at predicting crystal structures have not succeeded, mainly because the different interaction types are of comparable energy, and the delocalized and partial charges render the calculations of the ionic terms extremely unreliable. Clearly, the development of suitable crystal modeling techniques with predictive capabilities is one of the great needs of the field.

  11. Unconventional Density Waves in Organic Conductors and in Superconductors

    Science.gov (United States)

    Maki, K.; Dóra, B.; Virosztek, A.

    Unconventional density waves (UDW) are one of the ground states in metallic crystalline solids and have been speculated already in 1968. However, more focused studies on UDWstarted only recently, perhaps after the identification of the low temperature phase in α-(BEDT-TTF)2KHg(SCN)4 as unconventional charge density wave (UCDW) in 2002. More recently, the metallic phase of Bechgaard salts (TMTSF)2X with X=PF6 and ReO4 under both pressure and magnetic field appears to be unconventional spin density wave (USDW). The pseudogap regime of high T c superconductors LSCO, YBCO, Bi2212 and the one in CeCoIn5 belong to d-wave density waves (d-DW). In these identifications, the angular dependent magnetoresistance and the giant Nernst effect have played the crucial role. These are the simplest manifestations of the Landau quantization of quasiparticle energy in UDW in the presence of magnetic field (the Nersesyan effect). Also we speculate that UDW will be most likely found in α-(BEDT-TTF)2I3, α-(BEDT-TTF)2I2Br, κ-(BEDT-TTF)2Cu(NCS)2, κ-(BEDT-TTF)2Cu(CN)2Br, γ-(BEDT)2GaCl4 and in many other organic compounds.

  12. Carbon conductor- and binder-free organic electrode for flexible organic rechargeable batteries with high energy density

    Science.gov (United States)

    Kim, Tae Sin; Lim, Ji-Eun; Oh, Min-Suk; Kim, Jae-Kwang

    2017-09-01

    For the first time, we report a poly (2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA)-based organic electrode with 100 wt% active material loading. The electrochemical performance of the PTMA electrode for organic batteries was improved by replacing the aluminum current collector by graphite ones. The use of graphite current collector reduces the cell weight and increases its mechanical flexibility. The resulting battery with the new carbon conductor- and binder-free organic electrode with polyimide-based gel polymer electrolyte (GPE) displayed significantly higher increased energy density (470 Wh kg-1vs. cell weight), which is essential for making organic batteries competitive with conventional Li ion batteries.

  13. Next generation bioelectronics: Advances in fabrication coupled with clever chemistries enable the effective integration of biomaterials and organic conductors

    Science.gov (United States)

    Molino, Paul J.; Wallace, Gordon G.

    2015-01-01

    Organic bioelectronics is making an enormous impact in the field of tissue engineering, providing not just biocompatible, but biofunctional conducting material platforms. For their true potential to be reached, it is critical to integrate organic conductors with other biopolymers in a targeted manner, allowing the development of devices and scaffold architectures capable of delivering a number of physical, chemical, and electrical stimuli. Herein, we provide an overview of the methods currently being employed to tailor organic conductors for bioapplications, with a focus on the development of fabrication techniques vital to the development of the next generation of intelligent bionic devices.

  14. Next generation bioelectronics: Advances in fabrication coupled with clever chemistries enable the effective integration of biomaterials and organic conductors

    Directory of Open Access Journals (Sweden)

    Paul J. Molino

    2015-01-01

    Full Text Available Organic bioelectronics is making an enormous impact in the field of tissue engineering, providing not just biocompatible, but biofunctional conducting material platforms. For their true potential to be reached, it is critical to integrate organic conductors with other biopolymers in a targeted manner, allowing the development of devices and scaffold architectures capable of delivering a number of physical, chemical, and electrical stimuli. Herein, we provide an overview of the methods currently being employed to tailor organic conductors for bioapplications, with a focus on the development of fabrication techniques vital to the development of the next generation of intelligent bionic devices.

  15. Stretchable active-matrix organic light-emitting diode display using printable elastic conductors

    Science.gov (United States)

    Sekitani, Tsuyoshi; Nakajima, Hiroyoshi; Maeda, Hiroki; Fukushima, Takanori; Aida, Takuzo; Hata, Kenji; Someya, Takao

    2009-06-01

    Stretchability will significantly expand the applications scope of electronics, particularly for large-area electronic displays, sensors and actuators. Unlike for conventional devices, stretchable electronics can cover arbitrary surfaces and movable parts. However, a large hurdle is the manufacture of large-area highly stretchable electrical wirings with high conductivity. Here, we describe the manufacture of printable elastic conductors comprising single-walled carbon nanotubes (SWNTs) uniformly dispersed in a fluorinated rubber. Using an ionic liquid and jet-milling, we produce long and fine SWNT bundles that can form well-developed conducting networks in the rubber. Conductivity of more than 100Scm-1 and stretchability of more than 100% are obtained. Making full use of this extraordinary conductivity, we constructed a rubber-like stretchable active-matrix display comprising integrated printed elastic conductors, organic transistors and organic light-emitting diodes. The display could be stretched by 30-50% and spread over a hemisphere without any mechanical or electrical damage.

  16. Charge fluctuation, charge ordering, and zero-gap state in organic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Toshihiro, E-mail: toshi.takahashi@gakushuin.ac.jp [Department of Physics, Gakushuin University, Mejiro 1-5-1, Toshima-ku, Tokyo 171-8588 (Japan)

    2012-06-01

    We have carried out a series of measurements of angular dependence of solid-state NMR spectrum using single crystal samples on various organic molecular conductors, in order to investigate the natures of the electronic states at low temperatures. We confirmed a charge ordered insulating state in {alpha}-(BEDT-TTF){sub 2}I{sub 3} and large charge disproportionation in the metallic state of this salt. In another charge ordered system, {theta}-(BEDT-TTF){sub 2}RbZn(SCN){sub 4}, we observed unusual NMR line broadening, proportional to resonance shift, in the metallic state above the transition. We found that this broadening is due to charge disproportionation, or more correctly, due to the inhomogeneity of local susceptibility at nuclear sites and analyzed its dynamics. We observed similar broadening in various organic molecular conductors as well, such as {theta}-(BEDT-TTF){sub 2}CsZn(SCN){sub 4}, an exotic Bechgaad salt, (TMTSF){sub 2}FSO{sub 3}, and {lambda}-type BETS salts, {lambda}-(BETS){sub 2}(Fe,Ga)Cl{sub 4}. We found the mechanism of CD in each system is different, respectively.

  17. Spectroscopic investigation of some building blocks of organic conductors: A comparative study

    Science.gov (United States)

    Mukherjee, V.; Yadav, T.

    2017-04-01

    Theoretical molecular structures and IR and Raman spectra of di and tetra methyl substituted tetrathiafulvalene and tetraselenafulvalene molecules have been studied. These molecules belong to the organic conductor family and are immensely used as building blocks of several organic conducting devices. The Hartree-Fock and density functional theory with exchange functional B3LYP have been employed for computational purpose. We have also performed normal coordinate analysis to scale the theoretical frequencies and to calculate potential energy distributions for the conspicuous assignments. The exciting frequency and temperature dependent Raman spectra have also presented. Optimization results reveal that the sulphur derivatives possess boat shape while selenium derivatives possess planner structures. Natural bond orbitals analysis has also been performed to study second order interaction between donors and acceptors and to compute molecular orbital occupancy and energy.

  18. Multidimensional Nature of Molecular Organic Conductors Revealed by Angular Magnetoresistance Oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Pashupati Dhakal, Harukazu Yoshino, Jeong-Il Oh, Koichi Kikuchi, Michael J. Naughton

    2012-09-01

    Angle-dependent magnetoresistance experiments on organic conductors exhibit a wide range of angular oscillations associated with the dimensionality and symmetry of the crystal structure and electron energy dispersion. In particular, characteristics associated with 1, 2, and 3-dimensional electronic motion are separately revealed when a sample is rotated through different crystal planes in a magnetic field. Originally discovered in the TMTSF-based conductors, these effects are particularly pronounced in the related system (DMET){sub 2}I{sub 3}. Here, experimental and computational results for magnetoresistance oscillations in this material, over a wide range of magnetic field orientations, are presented in such a manner as to uniquely highlight this multidimensional behavior. The calculations employ the Boltzmann transport equation that incorporates the system's triclinic crystal structure, which allows for accurate estimates of the transfer integrals along the crystallographic axes, verifying the 1D, 2D and 3D nature of (DMET){sub 2}I{sub 3}, as well as crossovers between dimensions in the electronic behavior.

  19. Origin of anomalous magnetic breakdown frequencies in quasi-two-dimensional organic conductors

    Science.gov (United States)

    Sandhu, P. S.; Kim, Ju H.; Brooks, J. S.

    1997-11-01

    We investigate the origin of anomalous magnetic breakdown frequencies in the de Haas-van Alphen (dHvA) effect in quasi-two-dimensional organic conductors such as α-(BEDT-TTF)2KHg(SCN)4 and κ-(BEDT-TTF)2Cu(NCS)2. A tight-binding model based on their realistic band structure is constructed and solved numerically to compute the field dependence of the magnetization. The present model provides a natural description for the phenomenon of magnetic breakdown between coexisting closed and open Fermi surfaces and accounts for the experimentally observed frequencies that are forbidden in the semiclassical picture. We find that the appearance of these anomalous frequencies in the dHvA signal is a quantum-mechanical effect which arises from differences in field dependence of the states in the two partially occupied bands near the Fermi level.

  20. Application of mixed-organic-cation for high performance hole-conductor-free perovskite solar cells.

    Science.gov (United States)

    Xiao, Meng; Zhao, Li; Wei, Shoubin; Li, Yanyan; Dong, Binghai; Xu, Zuxun; Wan, Li; Wang, Shimin

    2017-09-15

    ABX3-type organic lead halide perovskites have gained increasing attention as light harvester for solar cells due to their high power conversion efficiency (PCE). Recently, it has become a trend to avoid the use of expensive hole-transport materials (HTMs) and precious metals, such as Au, to be competitive in future commercial development. In this study, we fabricated mixed-cation perovskite-based solar cells through one-step spin-coating using methylammonium (CH3NH3(+)) and formamidinium (HN=CHNH3(+)) cations to extend the optical absorption range into the red region and enhance the utilization of solar light. The synthesized hole-conductor-free cells with carbon electrode and mixed cations exhibited increased short-circuit current, outperforming the cells prepared with pure methylammonium, and PCE of 10.55%. This paper proposes an efficient approach for fabricating high-performance and low-cost perovskite solar cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Transport Properties of the Organic Conductor (TMTSF)2BrO4: Evidence of Variable Range Hopping

    DEFF Research Database (Denmark)

    Mortensen, Kell; Jacobsen, Claus Schelde; Bechgaard, Klaus

    1984-01-01

    A study of d.c. and microwave conductivity and thermoelectric power of the organic conductor (TMTSF)2BrO4 is presented. The transport properties are in qualitative agreement with charge transport via variable-range hopping among localized states. The localization is attributed to the anions, which...

  2. Magnetic Field-Temperature Phase Diagram of the Organic Conductor α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Christ, P.; Biberacher, W.; Kartsovnik, M. V.; Steep, E.; Balthes, E.; Weiss, H.; Müller, H.

    2000-04-01

    We present systematic magnetic torque studies of the ``magnetic field - temperature'' phase diagram of the layered organic conductor alpha-(BEDT-TTF)2KHg(SCN)4 at fields nearly perpendicular and nearly parallel to the highly conducting plane. The shape of the phase diagram is compared to that predicted for a charge-density-wave system in a broad field range.

  3. Electronic States in Quasi-one-Dimensional Copolymeric Sandwich Structures

    Institute of Scientific and Technical Information of China (English)

    刘德胜; 王鹿霞; 魏建华; 郑斌; 解士杰; 韩圣浩; 梅良模

    2001-01-01

    The electronic properties of xPA/nPPP/yPA sandwiched copo]ymers with a well-barrier-well structure have been studied by using a tight-binding calculation. It was found that the electronic properties of the neutral states of these sandwiched copolymers are sensitive to the constitutions of PPP and PA monomers and the interface coupling between PA and PPP. It is verified that the quantum tunnelling effect will occur at the lowest conductive state of xPA/nPPP/xPA copolymers.

  4. Quasi-one-dimensional scattering in a discrete model

    DEFF Research Database (Denmark)

    Valiente, Manuel; Mølmer, Klaus

    2011-01-01

    that more than one confinement-induced resonances appear due to the nonseparability of the center-of-mass and relative coordinates on the lattice. This is done by solving its corresponding Lippmann-Schwinger-like equation. We characterize the effective one-dimensional interaction and compare it with a model...

  5. Phonon scattering in quasi-one-dimensional structure

    Energy Technology Data Exchange (ETDEWEB)

    Bourahla, B., E-mail: bourahla_boualem@yahoo.f [Laboratoire de Physique et Chimie Quantique, Universite de Tizi Ouzou, BP 17 RP 15000 (Algeria); Laboratoire de Physique de l' etat Condense, UMR 6087, Universite du Maine, 72085 Le Mans (France); Nafa, O. [Laboratoire de Physique et Chimie Quantique, Universite de Tizi Ouzou, BP 17 RP 15000 (Algeria); Tigrine, R. [Laboratoire de Physique et Chimie Quantique, Universite de Tizi Ouzou, BP 17 RP 15000 (Algeria); Laboratoire de Physique de l' etat Condense, UMR 6087, Universite du Maine, 72085 Le Mans (France)

    2011-02-15

    We introduce a model to study a symmetric nanocontact, whereby its mechanical properties can be analyzed via the vibration spectra. The model system consists of two groups of triple semi-infinite atomic chains joined by atoms in between. The matching method theoretical approach is used to calculate the coherent reflection and transmission scattering probabilities, the characteristic vibration Green functions and densities of states (DOS), for the vibration components of the individual atomic sites that constitute a complete representation of the nanocontact domain boundaries. The nanocontact observables are numerically calculated for different cases of elastic hardening and softening, to investigate how the local dynamics can respond to changes in the microscopic environment on the nanocontact domain. The analysis of the vibration spectra and the DOS demonstrate the fluctuations, related to Fano resonances, due to the coherent coupling between traveling phonons and the localized vibration modes in the nanocontact domain.

  6. A Quasi-One-Dimensional CFD Model for Multistage Turbomachines

    Institute of Scientific and Technical Information of China (English)

    Olivier Léonard; Olivier Adam

    2008-01-01

    The objective of this paper is to present a fast and reliable CFD model that is able to simulate stationary and transient operations of multistage compressors and turbines. This analysis tool is based on an adapted version of the Euler equations solved by a time-marching, finite-volume method. The Euler equations have been extended by including source terms expressing the blade-flow interactions. These source terms are determined using the velocity triangles and a row-by-row representation of the blading at mid-span. The losses and deviations undergone by the fluid across each blade row are supplied by correlations. The resulting flow solver is a performance prediction tool based only on the machine geometry, offering the possibility of exploring the entire characteristic map of a multistage compressor or turbine. Its efficiency in terms of CPU time makes it possible to couple it to an optimization algorithm or to a gas turbine performance tool. Different test-cases are presented for which the calculated characteristic maps are compared to experimental ones.

  7. A disorder-enhanced quasi-one-dimensional superconductor.

    Science.gov (United States)

    Petrović, A P; Ansermet, D; Chernyshov, D; Hoesch, M; Salloum, D; Gougeon, P; Potel, M; Boeri, L; Panagopoulos, C

    2016-01-01

    A powerful approach to analysing quantum systems with dimensionality d>1 involves adding a weak coupling to an array of one-dimensional (1D) chains. The resultant quasi-1D (q1D) systems can exhibit long-range order at low temperature, but are heavily influenced by interactions and disorder due to their large anisotropies. Real q1D materials are therefore ideal candidates not only to provoke, test and refine theories of strongly correlated matter, but also to search for unusual emergent electronic phases. Here we report the unprecedented enhancement of a superconducting instability by disorder in single crystals of Na2-δMo6Se6, a q1D superconductor comprising MoSe chains weakly coupled by Na atoms. We argue that disorder-enhanced Coulomb pair-breaking (which usually destroys superconductivity) may be averted due to a screened long-range Coulomb repulsion intrinsic to disordered q1D materials. Our results illustrate the capability of disorder to tune and induce new correlated electron physics in low-dimensional materials.

  8. Wave Front Shaping in Quasi-One-Dimensional Waveguides

    CERN Document Server

    Böhm, Julian

    2016-01-01

    Using 10 monopole antennas reaching into a rectangular multi mode waveguide we shape the incident wave to create specific transport even after scattering events. Each antenna is attached to an IQ-Modulator, which allows the adjustment of the amplitude and phase in a broad band range of 6-18 GHz. All of them are placed in the near field of the other, thus the excitation of an individual antenna is influenced by the presence of the other antennas. Still these 10 antennas are sufficient to generate any combination of the 10 propagating modes in the far field. At the output the propagating modes are extracted using a movable monopole antenna that is scanning the field. If the modes are scattered in a scattering region, the incident wave can be adjusted in such a way, that the outgoing wave can still be adjusted as long as localization is not present.

  9. Localized surface plasmon of quasi-one-dimensional metallic nanostructures

    Science.gov (United States)

    Liu, Mingzhao

    2007-05-01

    The plasmon resonance of noble metal nanoparticles provides interesting optical properties in the visible and near-infrared region, and is highly tunable by varying the shape and the composition of the nanoparticles. The rod-like gold nanostructures can be synthesized by a seed-mediated method in aqueous surfactant solutions. Starting from different types of gold seeds, either single crystalline gold nanorods or penta-fold twinned gold bipyramids can be synthesized in decent yield with silver(I) added into the growth solution. These nanostructures have pronounced plasmon resonance varying in the 1˜2 eV range. The bipyramids are strikingly monodisperse in shape, which leads to the sharpest ensemble longitudinal plasmon resonance reported so far for metal colloid solutions. A mechanism based on the underpotential deposition of silver was thus suggested to explain the essential role of Ag(I) in the growth process. The optical spectra of the gold colloids were simulated with the finite-difference time-domain (FDTD) method. The results show excellent agreement with recent experimental optical spectra. The local field enhancement (|E|/|E0|) was studied at the plasmon resonance. Sharper structural features produce more significant enhancement and the largest enhancement of more than a factor of 200 is seen around the poles of the bipyramid. A large internal field enhancement by more than a factor of 30 is found for the bipyramids, which suggests that they will exhibit very strong optical nonlinearities. The plasmon can be further tuned by introducing the core/shell nanostructures such as metal/metal or metal/semiconductor nanorods. Following a simple procedure, a homogeneous layer of silver with 1-4 nm thickness can be plated onto the gold nanorods, which shifts the longitudinal plasmon mode of the nanorods toward blue. The silver layer can be converted to semiconductors silver sulfide or selenide, with the longitudinal plasmon resonance tuned toward red. The metal/semiconductor nanorods also present significant nonlinear optical properties. Finally, the optical properties of plasmon at low temperature were studied. Combining the experimental and theoretical work on this topic, it is found that the electron-phonon relaxation becomes less active, implying a higher quality factor of the plasmon resonance and therefore larger local field enhancement at lower temperature.

  10. Compaction of quasi-one-dimensional elastoplastic materials

    Science.gov (United States)

    Shaebani, M. Reza; Najafi, Javad; Farnudi, Ali; Bonn, Daniel; Habibi, Mehdi

    2017-06-01

    Insight into crumpling or compaction of one-dimensional objects is important for understanding biopolymer packaging and designing innovative technological devices. By compacting various types of wires in rigid confinements and characterizing the morphology of the resulting crumpled structures, here, we report how friction, plasticity and torsion enhance disorder, leading to a transition from coiled to folded morphologies. In the latter case, where folding dominates the crumpling process, we find that reducing the relative wire thickness counter-intuitively causes the maximum packing density to decrease. The segment size distribution gradually becomes more asymmetric during compaction, reflecting an increase of spatial correlations. We introduce a self-avoiding random walk model and verify that the cumulative injected wire length follows a universal dependence on segment size, allowing for the prediction of the efficiency of compaction as a function of material properties, container size and injection force.

  11. Organic-inorganic halide perovskite solar cell with CH3NH3PbI2Br as hole conductor

    Science.gov (United States)

    Zhang, Shufang; Zhang, Chenming; Bi, Enbing; Miao, Xiaoliang; Zeng, Haibo; Han, Liyuan

    2017-01-01

    Perovskite solar cells (PSCs) have attracted enormous interest as the most remarkably growing photovoltaic devices. With the power conversion efficiencies of PSCs excessing 20%, great challenges have been focused on the issues of cost and long-term stability which are majorly related to the hole transport materials. In contrast, the PSCs without special hole conductors show great potential for commercial applications due to their cost-effective and fairly stable features. However, the inferior charge separation at the CH3NH3PbI3 (MAPbI3) and back electrode interface limits the cells for high efficiency. Our strategy is to arrange suitable energy band alignment at the interface to enhance the charge separation. We herein report a MAPbI3/MAPbI2Br cascade structured PSC with MAPbI2Br majorly acting as a hole conductor. The conversion efficiency of the PSCs is greatly improved and a high efficiency of 15.83% is achieved. This new design of using organic-inorganic halide perovskites as hole conductors provides an efficient approach for improving the performance of low-cost PSCs.

  12. Hole-conductor-free perovskite organic lead iodide heterojunction thin-film solar cells: High efficiency and junction property

    Science.gov (United States)

    Shi, Jiangjian; Dong, Juan; Lv, Songtao; Xu, Yuzhuan; Zhu, Lifeng; Xiao, Junyan; Xu, Xin; Wu, Huijue; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

    2014-02-01

    Efficient hole-conductor-free organic lead iodide thin film solar cells have been fabricated with a sequential deposition method, and a highest efficiency of 10.49% has been achieved. Meanwhile, the ideal current-voltage model for a single heterojunction solar cell is applied to clarify the junction property of the cell. The model confirms that the TiO2/CH3NH3PbI3/Au cell is a typical heterojunction cell and the intrinsic parameters of the cell are comparable to that of the high-efficiency thin-film solar cells.

  13. Emergent Paramagnetism in D-and L-Alanine Crystals: Spin-Orbital Separation in Quasi-One-Dimensional N+H…O-Bonds%D-和L-丙氨酸晶体的突现顺磁性:准一维N+H…O-氢键的自旋-轨道分离

    Institute of Scientific and Technical Information of China (English)

    王文清; 沈新春; 张玉凤; 龚

    2013-01-01

    研究了与磁场强度相关的手性丙氨酸晶体的电子轨道运动的磁性质.根据丙氨酸单晶的两性离子(+NH3-C(CH3)H-CO2-)模型的手性和蛋白质中肽键晶格结构的螺旋性,当外加磁场为5 T,磁场方向平行于丙氨酸晶轴c(z)的极性N+H…O-氢键,观察到D-丙氨酸晶格中,氢原子的电子自旋翻转,在297.6 K直接突现顺磁性.L-丙氨酸则先发生电子自旋转向,然后在303.9 K突现顺磁性.实验发现:外加强磁场可以分裂手性丙氨酸晶格中氢键的简并顺磁态,并测出能差.本文进一步证明了准一维极性N+H…O-氢键在晶格中可以发生自旋-轨道分离,表现出一维物理的基本特征.%We investigated the field-dependent magnetic properties of chiral alanine crystals,especially associated with the electronic orbital motions.Based on the chirality of the zwitterionic model (+NH3-C(CH3)H-CO2-) and the helicity of the lattice structure of peptide bond in proteins,when an external field of 5 T was applied parallel to the preferred axis c(z) of the N+H…O-hydrogen bond in D-alanine,the electron spin-flip manifested emergent paramagnetism at 297.6 K.Because the spin magnetic dipole moment of hydrogen in L-alanine was originally aligned antiparallel to the field,the electron spins flipped firstly perpendicular to the field then manifested paramagnetism at 303.9 K.The magnetic field of 5 T split a degenerate energy level in the paramagnetic state of chiral alanine.Furthermore,the spin-orbital separation of the quasi-one dimensional N+H…O-hydrogen bond in the crystal lattice provided evidence for the hallmark of one-dimensional physics.

  14. Charge Transport in Antiferromagnetic Insulating Phase of Two-Dimensional Organic Conductor λ-(BETS)2FeCl4

    Science.gov (United States)

    Sugiura, Shiori; Shimada, Kazuo; Tajima, Naoya; Nishio, Yutaka; Terashima, Taichi; Isono, Takayuki; Kobayashi, Akiko; Zhou, Biao; Kato, Reizo; Uji, Shinya

    2016-06-01

    Resistance and dielectric constants have been measured in the antiferromagnetic insulating phase of the quasi-two-dimensional organic conductor λ-(BETS)2FeCl4 to understand charge transport. Nonlinear current-voltage characteristics are observed at low temperatures, which are explained by a charge transport model based on the electric-field dependent Coulomb potential between the thermally excited electron and hole. A small dip in the magnetic field dependence of the resistance is found at 1.2 T, which is ascribed to a spin-flop transition. The large difference between the in-plane and out-of-plane dielectric constants shows the two-dimensionality of the Coulomb potential, which is consistent with the charge transport model. The angular dependence of the metal-insulator transition field is determined, which suggests that the Zeeman effect of the 3d spins of the Fe ions plays an essential role.

  15. Electron Magnetic Resonance Fermi Surface Imaging. Applications to Organic Conductors and Sr2RuO4

    Science.gov (United States)

    Hill, S.; Kovalev, A.; Mola, M. M.; Palassis, C.; Mao, Z. Q.; Maeno, Y.; Qualls, J. S.

    We report detailed angle dependent studies of the metallic state microwave (40 to 200 GHz) magneto-conductivity of single crystal samples of the α-(BEDT-TTF)2KHg(SCN)4 organic charge density wave conductor, and the perovskite superconductor Sr2RuO4. We observe series' of resonant absorptions which we attribute to periodic orbit resonances - a phenomenon closely related to cyclotron resonance. By performing measurements on several samples, and in different electromagnetic field configurations, we are able to couple to different orbital modes (+ harmonics), which derive from deformations (warpings) of the quasi-one and quasi-two-dimensional Fermi surfaces of these compounds. These studies provide vital information concerning interlayer dispersion which, in turn, affects the Fermi surface nesting characteristics which are believed to play a crucial role in the low temperature physics of these exotic materials.

  16. Magnetic Torque Studies in Two-Dimensional Organic Conductor λ-(BETS)2FeCl4

    Science.gov (United States)

    Sugiura, Shiori; Shimada, Kazuo; Tajima, Naoya; Nishio, Yutaka; Terashima, Taichi; Isono, Takayuki; Kato, Reizo; Uji, Shinya

    2017-01-01

    Systematic measurements of the magnetic torque τ of the organic conductor λ-(BETS)2FeCl4 have been performed to investigate the magnetic properties. In the magnetic field dependence of τ, a very sharp structure is observed at ˜1.2 T, resulting from the spin-flop transition. A step-like behavior associated with small hysteresis appears at ˜10 T, which is caused by the antiferromagnetic insulator-paramagnetic metal (AFI-PM) transition. In the angular dependence of τ for magnetic fields in the b*-c plane, it is found that the zero-crossing angles significantly change with field and temperature. The changes provide reasonable evidence of the antiferromagnetic order of the π spins (not the Fe 3d spins) in the AFI phase. The AFI-PM transition field has a minimum when the magnetization of the 3d spins has a maximum as a function of field angle.

  17. Anomalous photo-induced response by double-pulse excitation in the organic conductor (EDO-TTF)2PF6

    Science.gov (United States)

    Onda, Ken; Ogihara, Sho; Ishikawa, Tadahiko; Okimoto, Yoichi; Shao, Xiangfeng; Nakano, Yoshiaki; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-ya

    2009-02-01

    We measured ultrafast reflectivity changes induced by double-pulse excitation in the organic conductor (EDO-TTF)2PF6. Using double-pulse excitation with a relatively high intensity, the sign of reflectivity change became reversed at around 0.8 ps and subsequently the reflectivity change reverted to that of the normal photo-induced state after about 1 ps. Using a optically phase-locked double-pulse with low intensity, we found that the temporal profile excited by an in-phase double-pulse differs from that by an out-of-phase double-pulse despite the time difference between the double-pulses being only 1.31 fs. This was true even when there is almost no overlap between each pulse in the double-pulse. These results indicate that the photo-response in this material to double-pulse excitation differs greatly from the linear sum of the responses to single pulses.

  18. First observation of angle-dependent Stark cyclotron resonance in bulk crystals: High-electric-field interlayer magnetotransport in a layered organic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, A.; Konoike, T.; Uchida, K. [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Osada, T., E-mail: osada@issp.u-tokyo.ac.j [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

    2010-06-01

    We report a novel angle-dependent magnetotransport phenomenon in layered conductors under strong interlayer electric fields. Interlayer conduction shows the Stark cyclotron resonance (SCR) when electron orbital motion becomes periodic in k-space. The SCR amplitude oscillates depending on magnetic field orientations. The conventional angle-dependent magnetoresistance oscillation (AMRO) switches to the angle-dependent SCR in high electric fields. We predict angle-dependent SCR due to electron orbital motion in layered conductors with coherent interlayer coupling. In addition, we demonstrate the expected switching from conventional AMRO to angle-dependent SCR in high electric fields using an organic conductor {alpha}-(BEDT-TTF){sub 2}NH{sub 4}Hg(SCN){sub 4}. This is the first observation of the SCR with orbital origin in bulk crystals.

  19. Magnetic breakdown in the organic conductor α-(BEDT-TTF)2KHg(SCN)4 in magnetic fields of up to 60 T

    Science.gov (United States)

    Honold, M. M.; Harrison, N.; Nam, M.-S.; Singleton, J.; Mielke, C. H.; Kurmoo, M.; Day, P.

    1998-09-01

    de Haas-van Alphen experiments on α-(BEDT-TTF)2KHg(SCN)4 in fields of up to 60 T reveal oscillations of the β frequency, a clear indication of magnetic breakdown at fields well above the kink transition. A study of the amplitude of the oscillations shows that the gap between the quasi-one-dimensional and quasi-two-dimensional Fermi-surface sheets is significantly smaller than predicted by band-structure calculations. We consider the implications for the spin-density-wave nesting and the quantum Hall effect.

  20. Electronic Structure of the ID Conductor K0.3MoO3 studied using resonant inelastic x-ray scattering and soft x-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Learmonth, T.; Glans, P.-A.; McGuinness, C.; Plucinski, L.; Zhang, Y.; Guo, J.-H.; Greenblatt, M.; Smith, K.E.

    2008-09-24

    The electronic structure of the quasi-one dimensional conductor K{sub 0.3}MoO{sub 3} has been measured using high resolution resonant inelastic x-ray scattering and x-ray absorption spectroscopy. The data is compared to that from the related two dimensional insulator {alpha}-MoO{sub 3}. Scattering features are observed from both oxides that are explained in terms of the band momentum selectivity of the scattering process, allowing a comparison of the scattering data to recent band structure calculations.

  1. Theoretical study of the zero-gap organic conductor α-(BEDT-TTF2I3

    Directory of Open Access Journals (Sweden)

    Akito Kobayashi, Shinya Katayama and Yoshikazu Suzumura

    2009-01-01

    Full Text Available The quasi-two-dimensional molecular conductor α-(BEDT-TTF2I3 exhibits anomalous transport phenomena where the temperature dependence of resistivity is weak but the ratio of the Hall coefficient at 10 K to that at room temperature is of the order of 104. These puzzling phenomena were solved by predicting massless Dirac fermions, whose motions are described using the tilted Weyl equation with anisotropic velocity. α-(BEDT-TTF2I3 is a unique material among several materials with Dirac fermions, i.e. graphene, bismuth, and quantum wells such as HgTe, from the view-points of both the structure and electronic states described as follows. α-(BEDT-TTF2I3 has the layered structure with highly two-dimensional massless Dirac fermions. The anisotropic velocity and incommensurate momenta of the contact points, ±k0, originate from the inequivalency of the BEDT-TTF sites in the unit cell, where ±k0 moves in the first Brillouin zone with increasing pressure. The massless Dirac fermions exist in the presence of the charge disproportionation and are robust against the increase in pressure. The electron densities on those inequivalent BEDT-TTF sites exhibit anomalous momentum distributions, reflecting the angular dependences of the wave functions around the contact points. Those unique electronic properties affect the spatial oscillations of the electron densities in the vicinity of an impurity. A marked behavior of the Hall coefficient, where the sign of the Hall coefficient reverses sharply but continuously at low temperatures around 5 K, is investigated by treating the interband effects of the magnetic field exactly. It is shown that such behavior is possible by assuming the existence of the extremely small amount of electron doping. The enhancement of the orbital diamagnetism is also expected. The results of the present research shed light on a new aspect of Dirac fermion physics, i.e. the emergence of unique electronic properties owing to the structure

  2. Phase transition in the organic conductor (TTM-TTP)I{3} studied by infrared and Raman spectroscopies

    Science.gov (United States)

    Świetlik, R.; Yakushi, K.; Yamamoto, K.; Kawamoto, T.; Mori, T.

    2004-04-01

    Polarised infrared reflectance (600 10000 cm-1) as well as Raman scattering spectra of the organic conductor (TTM-TTP)I{3} were investigated as a function of temperature, below and above the metal insulator phase transition at T=160 K. The IR electronic dispersion was analysed in terms of a Lorentz model and optical transport parameters were determined. The phase transition at 160 K has nearly no influence on IR spectra. The Raman scattering was studied for different excitations (λ =514.5, 632.6 and 785 nm). Within the C=C stretching region three Raman bands at 1436, 1453 and 1486 cm-1 were found and assigned to the three TTM-TTP modes of ag symmetry. Due to the phase transition the band at 1486 cm-1 splits into two lines at about 1487 and 1500 cm-1. We relate this splitting to an asymmetric deformation of TTM-TTP. Key words. TTM-TTP salt - organic metal - IR and Raman spectra - phase transition.

  3. Nonlocal magnetoresistance measurements of the organic zero-gap conductor α -(BEDT-TTF ) 2I3

    Science.gov (United States)

    Kamiya, Takeshi; Kawasugi, Yoshitaka; Ara, Masato; Tada, Hirokazu

    2017-02-01

    We prepared nonlocal spin valves based on single crystals of an organic multilayered zero-gap conductor α -(BEDT-TTF ) 2I3 and succeeded in evaluating the spin-diffusion length (1.1 μm) and relaxation time (3 ns) at 2.5 K under a static pressure of 1.6 GPa using a polyethylene naphthalate as a substrate. Although α -(BEDT-TTF ) 2I3 includes heavy atoms, such as iodine, it exhibited a rather long spin-relaxation time comparable to that of graphene. The spin-orbit interaction (SOI) estimated on the basis of the experimental values of the spin-relaxation time and carrier lifetime (1.2 ps) was 90 mK. The long spin-relaxation time and small SOI evaluated for α -(BEDT-TTF ) 2I3 are considered to originate from its layered structure in which spin scattering induced by surface defects is suppressed. In addition, the inversion asymmetry, which generates an extra term in the equation for the SOI, might be reduced in layered structures. These findings provide guiding principles for materials design in organic spintronics.

  4. Magnetic breakdown phenomenon in quasi-two-dimensional organic conductors: A quantum model inspired by a realistic band structure

    Science.gov (United States)

    Kim, Ju H.; Han, S. Y.; Brooks, J. S.

    1999-08-01

    We investigate the phenomenon of magnetic breakdown in quasi-two-dimensional organic conductors such as α-(ET)2KHg(SCN)4 and κ-(ET)2Cu(NCS)2 by constructing a tight-binding model based on a realistic band structure which is derived from the crystallographic data. We solve the model numerically to compute the magnetic field dependence of the magnetization and show that the present model accounts naturally for the experimentally observed magnetization oscillation frequencies that are forbidden in the semiclassical picture. The computed values of the fundamental and magnetic breakdown frequencies with no adjustable parameters are close to the experimentally measured values. For completeness, we carry out the computation for both canonical (fixed number of particles) and grand canonical (fixed chemical potential) ensembles, and show that the forbidden frequencies appear in both cases. Hence, the appearance of anomalous frequencies in the de Haas-van Alphen effect has a quantum-mechanical origin and arises from the interplay of electronic states from two partially occupied bands near the Fermi energy as a function of magnetic field. We also compute the temperature dependence of the magnetization and apply ad hoc the Lifshitz-Kosevich analysis to the amplitudes of the Fourier components at moderately high temperatures. This yields effective mass values for α-(ET)2KHg(SCN)4 in good agreement with experimental values.

  5. Interplay between the orbital quantization and Pauli effect in a charge-density-wave organic conductor

    Science.gov (United States)

    Kartsovnik, Mark; Andres, Dieter; Grigoriev, Pavel; Biberacher, Werner; Müller, Harald

    2004-04-01

    The interlayer magnetoresistance of the low-dimensional organic metal α-(BEDT-TTF) 2KHg(SCN) 4 under pressure shows features which are likely associated with theoretically predicted field-induced charge-density-wave (FICDW) transitions. At ambient pressure, a magnetic field strongly tilted towards the conducting layers induces a series of hysteretic anomalies. We attribute these anomalies to a novel kind of FICDW originating from a superposition of the orbital quantization of the nesting vector and Pauli effect on the charge-density wave.

  6. Interplay between the orbital quantization and Pauli effect in a charge-density-wave organic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Kartsovnik, Mark; Andres, Dieter; Grigoriev, Pavel; Biberacher, Werner; Mueller, Harald

    2004-04-30

    The interlayer magnetoresistance of the low-dimensional organic metal {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} under pressure shows features which are likely associated with theoretically predicted field-induced charge-density-wave (FICDW) transitions. At ambient pressure, a magnetic field strongly tilted towards the conducting layers induces a series of hysteretic anomalies. We attribute these anomalies to a novel kind of FICDW originating from a superposition of the orbital quantization of the nesting vector and Pauli effect on the charge-density wave.

  7. Inhomogeneous superconductivity in organic conductors: the role of disorder and magnetic field.

    Science.gov (United States)

    Haddad, S; Charfi-Kaddour, S; Pouget, J-P

    2011-11-23

    Several experimental studies have shown the presence of spatially inhomogeneous phase coexistence of superconducting and non-superconducting domains in low dimensional organic superconductors. The superconducting properties of these systems are found to be strongly dependent on the amount of disorder introduced in the sample regardless of its origin. The suppression of the superconducting transition temperature T(c) shows a clear discrepancy with the result expected from the Abrikosov-Gor'kov law giving the behavior of T(c) with impurities. On the basis of the time dependent Ginzburg-Landau theory, we derive a model to account for this striking feature of T(c) in organic superconductors for different types of disorder by considering the segregated texture of the system. We show that the calculated T(c) quantitatively agrees with experiments. We also focus on the effect of superconducting fluctuations on the upper critical fields H(c2) of layered superconductors showing slab structure where superconducting domains are sandwiched by non-superconducting regions. We found that H(c2) may be strongly enhanced by such fluctuations.

  8. Drude weight in quasi-two-dimensional organic conductors close to the Mott transition: Optical studies of the bandwidth, filling and temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Drichko, Natalia [Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, 194021 St. Petersburg (Russian Federation); 1. Physikalisches Institut, Universitaet Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany)], E-mail: drichko@pi1.physik.uni-stuttgart.de; Dumm, Michael; Faltermeier, Daniel; Dressel, Martin [1. Physikalisches Institut, Universitaet Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany); Merino, Jaime [Dept. de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid (Spain); Greco, Andres [Facultad de Ciencias Exactas Ingenieria y Agrimensura e Instituto de Fisica Rosario (UNR-CONICET), Rosario (Argentina)

    2007-09-01

    We explore the effects of electronic correlations in quasi-two-dimensional BEDT-TTF-based organic conductors with half, quarter and 1/5-filled bands. Close to the Mott transition but still on the metallic side, quasiparticles are observed in the 1/2-filled systems only at temperatures well below 100 K, with a considerable growth of the Drude-like contribution. In contrast, the 1/4-filled conductors show a zero-frequency conduction peak already at room temperature which increases slightly upon cooling. Basically no change with temperature is observed for the Drude contribution of the 1/5-filled compound. Optical studies allow us to investigate the formation of quasiparticles at low temperature for systems of different filling. The strongest effect is observed in 1/2-filled compounds, it becomes weaker in 1/4 filled, while in the 1/5-filled compound no change of the Dude-peak on temperature is seen.

  9. High-frequency magneto-conductivity studies of low-dimensional organic conductors

    CERN Document Server

    Schrama, J M

    2000-01-01

    Chapter 5 I report two studies of the angle dependence of FTRs in the high-frequency magneto-conductivity. The FTRs in kappa-(BEDT-TTF) sub 2 Cu(NCS) sub 2 and alpha-(BEDT- TTF) sub 2 KHg(SCN) sub 4 show two previously unknown corrugations in the Q1D Fermi-surface sections of the two materials. The FTRs in alpha-(BEDT-TTF) sub 2 KHg(SCN) sub 4 are investigated both in the density-wave state and near its collapse into a high-temperature, high-field state. In Chapter 6 a study of the millimetre-wave properties of (TMTSF) sub 2 ClO sub 4 at low temperatures is described. Finally, in Chapter 7 I present a study of the angle dependence of the superconductor order parameter in kappa-(BEDT-TTF) sub 2 Cu(NCS) sub 2 with a new millimetre-wave technique. In this thesis I present experimental studies of the millimetre-wave magneto-conductivity of the organic charge-transfer salts kappa-(BEDT-TTF) sub 2 Cu(NCS) sub 2 , alpha-(BEDT-TTF sub 2 KHg(SCN) sub 4 and (TMTSF) sub 2 ClO sub 4. A rotating resonant cavity insert was...

  10. The density wave state synchronized with the quantum oscillation in the organic conductor α-(BEDT-TTF) 2KHg(SCN) 4

    Science.gov (United States)

    Fujita, Toshiyuki; Sasaki, Takahiko; Yoneyama, Naoki; Kobayashi, Norio

    2004-04-01

    We report on the low-frequency AC higher harmonic response measurements in the density wave state of the layered organic conductor α-(BEDT-TTF) 2KHg(SCN) 4. The non-linear conduction in the longitudinal magnetoresistance is detected as the enhancement of the higher harmonic response. The magnitude of the non-linearity oscillates in the high magnetic field with the same frequency of the Shubnikov-de Haas oscillations. The observation is suggestive of the presence of the successive field-induced transition of the density wave state synchronized with the quantum oscillation in high magnetic fields.

  11. The density wave state synchronized with the quantum oscillation in the organic conductor {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Toshiyuki; Sasaki, Takahiko; Yoneyama, Naoki; Kobayashi, Norio

    2004-04-30

    We report on the low-frequency AC higher harmonic response measurements in the density wave state of the layered organic conductor {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4}. The non-linear conduction in the longitudinal magnetoresistance is detected as the enhancement of the higher harmonic response. The magnitude of the non-linearity oscillates in the high magnetic field with the same frequency of the Shubnikov-de Haas oscillations. The observation is suggestive of the presence of the successive field-induced transition of the density wave state synchronized with the quantum oscillation in high magnetic fields.

  12. Charge Transport and Insulator-Conductor Transition of li Salt Doped Polyaniline

    Science.gov (United States)

    Joo, J.; Jung, J. H.; Kim, B. H.; Moon, B. W.; Kim, J. Y.; Chang, S. H.; Ryu, K. S.

    2001-04-01

    Charge transport properties such as temperature dependent dc conductivity [σdc(T)] and thermoelectric power [S(T)], electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS) for various Li salt (LiPF6, LiBF4, LiAsF6, and LiClO4) doped polyaniline (PAN) samples are compared to those of protonic acid (HCl) doped PAN (PAN-ES) samples. The room temperature σdc of Li salt doped PANs varies from 1 to 10-7 S/cm depending on dopants used. The σdc(T) of the systems follows a quasi one-dimensional variable range hopping model, which is similar to PAN-ES. The S(T) of PAN-LiPF6 shows the metallic behavior. With increasing doping level, the insulator-conductor transition is observed in the results of σdc and the density of states obtained from EPR. From XPS experimetns, the doping level of the systems is estimated. The insulator-conductor transition of Li salt doped PANs is compared to that of PAN-ES samples and the charge transport properties of NaPF6 doped PANs are presented.

  13. Measurement of interlayer spin diffusion in the organic conductor {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]X, X=Cl, Br

    Energy Technology Data Exchange (ETDEWEB)

    Antal, Agnes; Feher, Titusz [Institute of Physics, Budapest University of Technology and Economics, and Condensed Matter Research Group of the Hungarian Academy of Sciences, P.O.Box 91, H-1521 Budapest (Hungary); Nafradi, Balint [Institute of Physics, Budapest University of Technology and Economics, and Condensed Matter Research Group of the Hungarian Academy of Sciences, P.O.Box 91, H-1521 Budapest (Hungary); Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Gaal, Richard; Forro, Laszlo [Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Janossy, Andras, E-mail: atj@szfki.h [Institute of Physics, Budapest University of Technology and Economics, and Condensed Matter Research Group of the Hungarian Academy of Sciences, P.O.Box 91, H-1521 Budapest (Hungary)

    2010-06-01

    In organic conductors the overlap integral between layers is small, in-plane momentum scattering is rapid and transport perpendicular to the layers is expected to be blocked. We present a high frequency conduction electron spin resonance (CESR) study in the layered organic metals {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]X, X=Cl, Br, which verifies that the inter-layer spin hopping is effectively blocked. The method relies on resolving the CESR lines of adjacent layers in which the orientation of the g-factor tensors differs. We find that at ambient pressure and in the metallic phase the electron spin diffusion is two dimensional in both the X=Cl and Br compounds, i.e. electrons diffuse longer than the spin lifetime within a single molecular layer without inter-layer hopping. Application of pressure at 250 K increases rapidly the inter-layer hopping rate of spins.

  14. The Second Threshold Field of Charge-Density-Wave Conductor Rb0.3MoO3 in High Temperature Range

    Institute of Scientific and Technical Information of China (English)

    LI Da-Hua; XIONG Rui; WANG Jun-Feng; LI Chang-Zhen; YIN Di; YI Fan; TANG Wu-Feng; SHI Jing

    2005-01-01

    @@ The switching and threshold properties of quasi-one-dimensional charge-density-wave conductor rubidium blue bronze Rb0.3MoO3 single crystals are investigated in a comparative high and large temperature range. Beyond the limit temperature 50 K of Littlewood's theory, even up to about 100K, typical sharp switching to negative or zero differential resistance is observed in E-I characteristic curves. Correspondingly, an obvious switching between two conducting states, from a lowly conducting state to a highly conducting state, is observed in the I-E characteristic curves in the same temperature range. Temperature dependence of the second threshold field ET2 accompanied by this kind of high field switching behaviour is firstly obtained. These new observations are discussed in the mechanism of the current inhomogeneity and redistribution due to the existence of transverse energy barriers suggested by Zhang et al. [Solid State Commun. 85 (1993) 121

  15. Non-Linear Conduction in the Density Wave State of Quasi-Two Dimensional Organic Conductor α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Fujita, Toshiyuki; Sasaki, Takahiko; Yoneyama, Naoki; Kobayashi, Norio

    2004-06-01

    Current-voltage characteristics are measured in the quasi-two dimensional organic conductor α-(BEDT-TTF)2KHg(SCN)4 at temperatures down to 0.5 K and in the magnetic field up to 25 T. The non-linear conduction with a threshold electric field is found in the density wave state. The features of threshold electric field obtained in the low magnetic field region are explained by the unconventional charge density wave model. In the high magnetic field region, where the Shubnikov-de Haas oscillations appear, the current-voltage characteristics reveal that the density wave state synchronizes with the filling of the electron on the Landau level and continues even above a kink field 23 T.

  16. Current orientation and contact distance dependence of rapid voltage oscillations in the organic conductor β''-[bis(ethylenedithio)tetrathiafulvalene]3(HSO4)2

    Science.gov (United States)

    Wakita, Hitoshi; Tamura, Kozo; Ozawa, Tatsuhiko; Bando, Yoshimasa; Kawamoto, Tadashi; Mori, Takehiko

    2010-12-01

    In an organic conductor β″-[bis(ethylenedithio)tetrathiafulvalene]3(HSO4)2, characteristic voltage oscillation is observed in the negative differential resistance region of the nonlinear conductivity below the metal-insulator transition at 125 K. The observed frequency f is 4-25 kHz and increases linearly with the collective current Jco. The oscillation appears in the two crystal directions of the conducting layer in agreement with the two-dimensional nonstripe charge order, where the anisotropy of the Jco/f slope is about two. The voltage oscillation disappears when the contact distance is larger than 0.02 cm, and at the same time the current-voltage characteristics loses a sharp negative resistance region. Since this critical length corresponds to the characteristic domain size of the charge order, the observed oscillation is interpreted by coherent transport of charge order which can move in different two directions.

  17. Magnetic ground state of quasi-two-dimensional organic conductor, τ-(EDO-S,S-DMEDT-TTF)2(AuCl2)1+y

    Science.gov (United States)

    Nakanishi, T.; Yasuzuka, S.; Yoshino, H.; Fujiwara, H.; Sugimoto, T.; Nishio, Y.; Kajita, K.; Anyfantis, G. A.; Papavassiliou, G. C.; Murata, K.

    2006-11-01

    To understand the interplay between transport and magnetic properties, quasi-two-dimensional (Q2D) organic conductor τ-(EDO-S,S-DMEDTTTF)2(AuCl2)1+y was studied by measurements of electric resistivity ( ρa, ρc), magnetoresistance (MR), susceptibility (χ) and specific heat (C) in the temperature region between 1 K and 300 K. In spite of the fact that the drastic changes were observed in ρa, ρc, MR and χ at TC = 20 K, no anomaly was seen in C. The concentration of spins estimated from M-H curve is about 360 ppm, which is difficult to detect anomaly in C. These data suggest that the number of spins is very small in the ground state like spin-glass system.

  18. NMR study on the quasi one-dimensional quantum spin magnet with ladder structure

    Science.gov (United States)

    Kobori, Shohei; Matsui, Kazuki; Kuwahara, Hideki; Goto, Takayuki; Zhang, Xiao; Nakano, Yuki; Nishihara, Sadafumi; Inoue, Katsuya; Sasaki, Takahiko

    2016-12-01

    The two-legged spin ladder Cu(CO3)0.5(ClO4)(H2O)0.5(NH3)2.5 consists of a rung formed by two Cu(II)'s and of a spacing molecule CO3^{2-} between each two rungs. The non-centrosymmetric shape of CO3^{2-} molecule brings a slight bond alternation along the leg, and hence the system can be considered as an alternating spin chain, which is confirmed so far by the temperature dependence of magnetic susceptibility. In order to investigate its spin state at low temperatures, we have performed experiments of 1H-NMR, magnetization and specific heat under wide range of magnetic field, and have found the critical diverging of longitudinal relaxation rate 1/ T 1, the spectral broadening and the lambda-type anomaly in specific heat at T N≃ 3.4 K, indicating the existence of long range magnetic order. In paramagnetic state well above T N, 1/ T 1 showed a power-law temperature dependence, suggesting the realization of Tomonaga Luttinger liquid state.

  19. Role of Lattice Coupling in Establishing Electronic and Magnetic Properties in Quasi-One-Dimensional Cuprates

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W. S.; Johnston, S.; Moritz, B.; Lee, J.; Yi, M.; Zhou, K. J.; Schmitt, T.; Patthey, L.; Strocov, V.; Kudo, K.; Koike, Y.; van den Brink, J.; Devereaux, T. P.; Shen, Z. X.

    2013-06-25

    High resolution resonant inelastic x-ray scattering has been performed to reveal the role of lattice coupling in a family of quasi-1D insulating cuprates, Ca2+5xY2-5xCu5O10. Site-dependent low-energy excitations arising from progressive emissions of a 70 meV lattice vibrational mode are resolved for the first time, providing a direct measurement of electron-lattice coupling strength. We show that such electron-lattice coupling causes doping-dependent distortions of the Cu-O-Cu bond angle, which sets the intrachain spin exchange interactions. Our results indicate that the lattice degrees of freedom are fully integrated into the electronic behavior in low-dimensional systems.

  20. Limits to metallic conduction in atomic-scale quasi-one-dimensional silicon wires.

    Science.gov (United States)

    Weber, Bent; Ryu, Hoon; Tan, Y-H Matthias; Klimeck, Gerhard; Simmons, Michelle Y

    2014-12-12

    The recent observation of ultralow resistivity in highly doped, atomic-scale silicon wires has sparked interest in what limits conduction in these quasi-1D systems. Here we present electron transport measurements of gated Si:P wires of widths 4.6 and 1.5 nm. At 4.6 nm we find an electron mobility, μ(el)≃60  cm²/V s, in excellent agreement with that of macroscopic Hall bars. Metallic conduction persists to millikelvin temperatures where we observe Gaussian conductance fluctuations of order δG∼e²/h. In thinner wires (1.5 nm), metallic conduction breaks down at G≲e²/h, where localization of carriers leads to Coulomb blockade. Metallic behavior is explained by the large carrier densities in Si:P δ-doped systems, allowing the occupation of all six valleys of the silicon conduction band, enhancing the number of 1D channels and hence the localization length.

  1. Investigation of quasi-one-dimensional finite phononic crystal with conical section

    Indian Academy of Sciences (India)

    Zhiqiang Fu; Shuyu Lin; Shi Chen; Xiaojun Xian; Chenghui Wang

    2014-12-01

    In this paper, we studied the propagation of elastic longitudinal waves in quasi-onedimensional (1D) finite phononic crystal with conical section, and derived expressions of frequencyresponse functions. It is found that, contrary to the 1D phononic crystal with a constant section, the value of attenuation inside the band gaps decreases quickly when cross-sectional area increases, and the initial frequency also decreases, but the cut-off frequency increases, thus the width of the band gap increases. The effects of lattice constant and the filling fraction on the band gap are also analysed, and the change trends of the initial frequency and cut-off frequency are consistent with those of constant section. It is shown that the results using this method are in good agreement with the results analysed by the finite element software, ANSYS.We hope that the results will be helpful in practical applications of phononic crystals.

  2. CONDUCTANCE IN DIFFUSIVE QUASI-ONE-DIMENSIONAL PERIODIC WAVEGUIDES: A SEMICLASSICAL AND RANDOM MATRIX STUDY

    OpenAIRE

    ZUÑIGA VUKUSICH, JAIME MIGUEL

    2011-01-01

    En esta tesis estudiamos propiedades de transporte cuántico en guías de onda finitas periódicas quasi-unidimensionales, cuya dinámica clásica asociada es difusiva. Nos enfocamos en el límite semiclásico el cual nos permite emplear un modelo de Teoria de Matrices Aleatorias (TMA) para describir el sistema. El requisito de difusión normal de la dinámica clásica restringe la configuración de la celda unitaria a tener horizonte finito, y significa que los ensembles apropiados de TMA son los en...

  3. Quantum ballistic transport by interacting two-electron states in quasi-one-dimensional channels

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Danhong [Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117 (United States); Center for High Technology Materials, University of New Mexico, 1313 Goddard St SE, Albuquerque, New Mexico 87106 (United States); Gumbs, Godfrey [Center for High Technology Materials, University of New Mexico, 1313 Goddard St SE, Albuquerque, New Mexico 87106 (United States); Abranyos, Yonatan [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States); Pepper, Michael; Kumar, Sanjeev [Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE (United Kingdom); London Centre for Nanotechnology, 17-19 Gordon Street, London, WC1H 0AH (United Kingdom)

    2015-11-15

    For quantum ballistic transport of electrons through a short conduction channel, the role of Coulomb interaction may significantly modify the energy levels of two-electron states at low temperatures as the channel becomes wide. In this regime, the Coulomb effect on the two-electron states is calculated and found to lead to four split energy levels, including two anticrossing-level and two crossing-level states. Moreover, due to the interplay of anticrossing and crossing effects, our calculations reveal that the ground two-electron state will switch from one anticrossing state (strong confinement) to a crossing state (intermediate confinement) as the channel width gradually increases and then back to the original anticrossing state (weak confinement) as the channel width becomes larger than a threshold value. This switching behavior leaves a footprint in the ballistic conductance as well as in the diffusion thermoelectric power of electrons. Such a switching is related to the triple spin degeneracy as well as to the Coulomb repulsion in the central region of the channel, which separates two electrons away and pushes them to different channel edges. The conductance reoccurrence region expands from the weak to the intermediate confinement regime with increasing electron density.

  4. Atom-light interactions in quasi-one-dimensional nanostructures: A Green's-function perspective

    Science.gov (United States)

    Asenjo-Garcia, A.; Hood, J. D.; Chang, D. E.; Kimble, H. J.

    2017-03-01

    Based on a formalism that describes atom-light interactions in terms of the classical electromagnetic Green's function, we study the optical response of atoms and other quantum emitters coupled to one-dimensional photonic structures, such as cavities, waveguides, and photonic crystals. We demonstrate a clear mapping between the transmission spectra and the local Green's function, identifying signatures of dispersive and dissipative interactions between atoms. We also demonstrate the applicability of our analysis to problems involving three-level atoms, such as electromagnetically induced transparency. Finally we examine recent experiments, and anticipate future observations of atom-atom interactions in photonic band gaps.

  5. Apparent power-law behavior of conductance in disordered quasi-one-dimensional systems.

    Science.gov (United States)

    Rodin, A S; Fogler, M M

    2010-09-03

    The dependence of hopping conductance on temperature and voltage for an ensemble of modestly long one-dimensional wires is studied numerically using the shortest-path algorithm. In a wide range of parameters this dependence can be approximated by a power law rather than the usual stretched-exponential form. The relation to recent experiments and prior analytical theory is discussed.

  6. Dissipation and entropy production in deterministic heat conduction of quasi-one-dimensional systems.

    Science.gov (United States)

    Morriss, Gary P; Truant, Daniel P

    2013-06-01

    We explore the consequences of a deterministic microscopic thermostat-reservoir contact mechanism. With different temperature reservoirs at each end of a two-dimensional system, a heat current is produced and the system has an anomalous thermal conductivity. The microscopic form for the local heat flux vector is derived and both the kinetic and potential contributions are calculated. The total heat flux vector is shown to satisfy the continuity equation. The properties of this nonequilibrium steady state are studied as functions of system size and temperature gradient, identifying key scaling relations for the local fluid properties and separating bulk and boundary effects. The local entropy density calculated from the local equilibrium distribution is shown to be a very good approximation to the entropy density calculated directly from the velocity distribution even for systems that are far from equilibrium. The dissipation and kinetic entropy production and flux are compared quantitatively and the differing mechanisms discussed within the Bhatnagar-Gross-Krook approximation. For equal-temperature reservoirs the entropy production near the reservoir walls is shown to be proportional to the local phase space contraction calculated from the tangent space dynamics. However, for unequal temperatures, the connection between local entropy production and local phase space contraction is more complicated.

  7. Dynamical spin injection at a quasi-one-dimensional ferromagnet-graphene interface

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.; Ahmadi, A.; Mucciolo, E. R.; Barco, E. del [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Cherian, C. T. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Graphene Research Center, National University of Singapore, Singapore 117542 (Singapore); Özyilmaz, B. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); NanoCore, 4 Engineering Drive 3, National University of Singapore, Singapore 117576 (Singapore); Graphene Research Center, National University of Singapore, Singapore 117542 (Singapore); NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Singapore 117456 (Singapore)

    2015-01-19

    We present a study of dynamical spin injection from a three-dimensional ferromagnet into two-dimensional single-layer graphene. Comparative ferromagnetic resonance (FMR) studies of ferromagnet/graphene strips buried underneath the central line of a coplanar waveguide show that the FMR linewidth broadening is the largest when the graphene layer protrudes laterally away from the ferromagnetic strip, indicating that the spin current is injected into the graphene areas away from the area directly underneath the ferromagnet being excited. Our results confirm that the observed damping is indeed a signature of dynamical spin injection, wherein a pure spin current is pumped into the single-layer graphene from the precessing magnetization of the ferromagnet. The observed spin pumping efficiency is difficult to reconcile with the expected backflow of spins according to the standard spin pumping theory and the characteristics of graphene, and constitutes an enigma for spin pumping in two-dimensional structures.

  8. Emergent quasi-one-dimensionality in a kagome magnet: A simple route to complexity

    Science.gov (United States)

    Gong, Shou-Shu; Zhu, Wei; Yang, Kun; Starykh, Oleg A.; Sheng, D. N.; Balents, Leon

    2016-07-01

    We study the ground-state phase diagram of the quantum spin-1 /2 Heisenberg model on the kagome lattice with first- (J10 ) by means of analytical low-energy field theory and numerical density-matrix renormalization group (DMRG) studies. The results offer a consistent picture of the Jd-dominant regime in terms of three sets of spin chains weakly coupled by the ferromagnetic interchain interactions J1 ,2. When either J1 or J2 is much stronger than the other one, the model is found to support one of two cuboctohedral phases, cuboc1, and cuboc2. These cuboc states host noncoplanar long-ranged magnetic order and possess finite scalar spin chirality. However, in the compensated regime J1≃J2 , a valence bond crystal phase emerges between the two cuboc phases. We find excellent agreement between an analytical theory based on coupled spin chains and unbiased DMRG calculations, including at a very detailed level of comparison of the structure of the valence bond crystal state. To our knowledge, this is the first such comprehensive understanding of a highly frustrated two-dimensional quantum antiferromagnet. We find no evidence of either the one-dimensional gapless spin liquid or the chiral spin liquids, which were previously suggested by parton mean-field theories.

  9. Surface engineered two-dimensional and quasi-one-dimensional nanomaterials for electronic and optoelectronic devices

    Science.gov (United States)

    Du, Xiang

    As the sizes of individual components in electronic and optoelectronic devices approach nano scale, the performance of the devices is often determined by surface properties due to their large surface-to-volume ratio. Surface phenomena have become one of the cornerstones in nanoelectronic industry. For this reason, research on the surface functionalization has been tremendous amount of growth over the past decades, and promises to be an increasingly important field in the future. Surface functionalization, as an effective technique to modify the surface properties of a material through a physical or chemical approach, exhibits great potential to solve the problems and challenges, and modulate the performance of nanomaterials based functional devices. Surface functionalization drives the developments and applications of modern electronic and optoelectronic devices fabricated by nanomaterials. In this thesis, I demonstrate two surface functionalization approaches, namely, surface transfer doping and H2 annealing, to effectively solve the problems and significantly enhance the performance of 2D (single structure black phosphorus (BP) and heterostructure graphene/Si Schottky junction), and quasi-1D (molybdenum trioxide (MoO 3) nanobelt) nanomaterials based functional devices, respectively. In situ photoelectron spectroscopy (PES) measurements were also carried out to explore the interfacial charge transfer occurring at the interface between the nanostructures and doping layers, and the gap states in MoO 3 thin films, which provides the underlying mechanism to understand and support our device measurement results. In the first part of this thesis, I will discuss the first surface functionalization approach, namely, surface transfer doping, to effectively modulate the ambipolar characteristics of 2D few-layer BP flakes based FETs. The ambipolar characteristics of BP transistors were effectively modulated through in situ surface functionalization with cesium carbonate (Cs2CO3) and MoO3, respectively. Cs2CO3 was found to strongly electron dope black phosphorus. The electron mobility of black phosphorus was significantly enhanced to ˜27 cm2V-1s-1 after 10 nm Cs2CO3 modification, indicating a greatly improved electron transport behavior. In contrast, MoO3 decoration demonstrated a giant hole doping effect. In situ PES characterization confirms the interfacial charge transfer between black phosphorus and doping layers. This doping can also modulate the Schottky junctions formed between metal contacts and black phosphorus flakes, and hence to enhance the responsivity of black phosphorus based photodetectors. These findings coupled with the tunable nature of the surface transfer doping scheme ensure black phosphorus as a promising candidate for further complementary logic electronics. Following the same surface transfer doping technique, I will demonstrate a remarkable performance enhancement of graphene/Si Schottky junction based self-powered photodetectors via surface modification with MoO3 thin film. It was found that the photocurrent responsivity of MoO3 doped graphene/Si photodetectors was highly increased under a wide spectrum of illuminated light from ultraviolet to near infrared. The current on-off ratio reached up to ˜104 under illumination of 500 nm light with intensity of ˜62 muWcm-2. More importantly, the external quantum efficiency of graphene/Si devices was significantly enhanced up to ˜80% by almost four times in the visible light region after MoO3 functionalization. The largely improved photodetecting performance originates from the increased Schottky barrier height at the graphene/Si interface as well as the reduced series resistance after MoO3 modification, which was further corroborated by the in situ PES and electrical transport characterizations. These observations promise a simple method to effectively modify the graphene/Si Schottky junction based self-powered photodetectors and thus significantly enhance their photodetecting performance. After discussion of the first surface functionalization method, next I will introduce the second approach which is H2 annealing, to greatly extend the photoresponse range of single MoO3 nanobelt based photodetector from UV to visible light by introducing substantial gap states. After annealing, the conductance of MoO3 nanobelt was largely enhanced; at the same time, the photodetector possessed wide visible spectrum response. As corroborated by in situ PES investigations, such strong wide spectrum photoresponse arises from the largely enriched oxygen vacancies and gap states in MoO3 nanobelt after H2 annealing. These results open up a new avenue to extend the wide bandgap metal oxide nanomaterials based optoelectronics devices with efficient visible light response through surface modification, i.e. the introduction of the high density of carefully engineered gap states.

  10. Raman scattering investigation of the quasi-one-dimensional superconductor Ta₄Pd₃Te₁₆.

    Science.gov (United States)

    Chen, D; Richard, P; Song, Z-D; Zhang, W-L; Wu, S-F; Jiao, W H; Fang, Z; Cao, G-H; Ding, H

    2015-12-16

    We have performed polarized Raman scattering measurements on the newly discovered superconductor Ta4Pd3Te16 (T(c) = 4.6 K). We observe 28 out of 33 Raman active modes, with frequencies in good accordance with first-principles calculations. Although most of the phonons observed vary only slightly with temperature and do not exhibit any asymmetric profile that would suggest strong electron-phonon coupling, the linewidth of the A(g) phonon mode at 89.9 cm(-1) shows an unconventional increase with temperature decreasing, which is possibly due to a charge-density-wave transition or the emergence of charge-density-wave fluctuations below a temperature estimated to fall in the 140-200 K range.

  11. Faraday waves in quasi-one-dimensional superfluid Fermi-Bose mixtures

    DEFF Research Database (Denmark)

    Abdullaev, F. Kh.; Ögren, Magnus; Sørensen, Mads Peter

    2013-01-01

    The generation of Faraday waves in superfluid Fermi-Bose mixtures in elongated traps is investigated. The generation of waves is achieved by periodically changing a parameter of the system in time. Two types of modulations of parameters are considered: a variation of the fermion-boson scattering...

  12. Sensitivity analysis explains quasi-one-dimensional current transport in two-dimensional materials

    DEFF Research Database (Denmark)

    Boll, Mads; Lotz, Mikkel Rønne; Hansen, Ole;

    2014-01-01

    . The sensitivity analysis presents a formal definition of quasi-1D current transport, which was recently observed experimentally in chemical-vapor-deposition graphene. Our numerical model for calculating sensitivity is verified by comparing the model to analytical calculations based on conformal mapping...

  13. Revealing origin of quasi-one dimensional current transport in defect rich two dimensional materials

    DEFF Research Database (Denmark)

    Lotz, Mikkel Rønne; Boll, Mads; Hansen, Ole;

    2014-01-01

    The presence of defects in graphene have for a long time been recognized as a bottleneck for its utilization in electronic and mechanical devices. We recently showed that micro four-point probes may be used to evaluate if a graphene film is truly 2D or if defects in proximity of the probe will lead...... to a non-uniform current flow characteristic of lower dimensionality. In this work, simulations based on a finite element method together with a Monte Carlo approach are used to establish the transition from 2D to quasi-1D current transport, when applying a micro four-point probe to measure on 2D...... contacts is compared to the micro four-point probe conductance measurements and we find that the micro four-point probe tends to measure a slightly higher conductance in samples containing defects. (C) 2014 AIP Publishing LLC....

  14. The application of quasi-one dimensional nano-materials in nanoelectronic devices

    Science.gov (United States)

    Zhang, Li

    As the scaling of silicon based electronic devices is approaching limitations set by the physical and materials properties, several nano-sized materials have gained much interest as possible substitutions of silicon for future electronics. This thesis focuses on carbon nanotubes (CNTs), graphene nanoribbons (GNRs) and germanium nanowires (GeNWs) due to their unique properties. Single walled carbon nanotubes are molecular quantum wires (diameter ˜1nm) which are highly chemically stable and exhibit outstanding electrical conductivity. However, typical synthesis of SWNTs yields a mixture of both metallic and semiconducting varieties with a range of diameters. Several methods have been reported to separate SWNTs and anion exchange (IEC) chromatography has shown the most promise for electronic type separation. In the first part of the dissertation, I will discuss the characterization of IEC separation efficiency by combining spectroscopy and electrical measurements. In the early experiment, the SWNTs were separated according to diameter and electronic types and the separation efficiency decreased with increasing tube diameter. The separation efficiency was much improved by using the new DNA sequence to suspend the SWNTs and single-chirality-enrichment was achieved. Graphene is single layer graphite, which is predicted to exhibit bandgaps useful for room temperature transistor operations with excellent switching speed and high mobilities when made into narrow ribbons (sub-10 nm). The all-semiconducting nature of sub-10 nm GNRs could bypass the problem of extreme chirality dependence of metal or semiconductor carbon nanotubes (CNTs) for future electronics. Currently, making GNRs remains challenging by lithographic, chemical or sonochemical methods. It is difficult to obtain GNRs with smooth edges and controllable width at high yields. In the second part of the thesis, I will show an interesting approach to making GNRs by unzipping multiwalled carbon nanotubes (MWNTs) by plasma etching of nanotubes partially embedded in a polymer film. The GNRs exhibit smooth edges and a narrow width distribution between 10-20 nm. Raman spectroscopy and electrical transport measurements reveal high quality of the GNRs. Germanium nanowires (GeNWs) are another potential material to address the future device scaling limitations owing to their high hole and electron mobilities. However, the device performance is limited due to insufficient electrostatic control over charge carriers in the channel in the typical back-gate or top-gate geometry. Mobility analysis based on capacitance modeling alone without direct measurement could give errors due to various uncertainties. In the last part of this dissertation, I will demonstrate a novel surround gate structure of GeNW FETs using a novel self-aligned fabrication approach. Individual surround gate (SG) GeNW FETs show improved switching over GeNW FETs with planar gate stacks owing to improved electrostatics. FET devices comprised of multiple quasi-aligned SG GeNWs in parallel afford on-currents exceeding 0.1 mA at low source-drain bias voltages. Direct experimental evidence show that SG nanowire transistors exhibit higher capacitance and better electrostatic gate control than top-gated devices, and are the most promising structure for future high performance nanoelectronics.

  15. Template-assisted synthesis and characterisation of quasi-one-dimensional ceramic nanomaterials

    OpenAIRE

    2010-01-01

    The major results of the present work are the template-assisted (porous alumina or polycarbonate) manufacturing of nanowires, nanorods or nanotubes with tailored dimensions, composition, and physical-chemical properties, as well as optimisation of routine producing of alumina templates with the nanochannels open through from both ends. A successful attempt to alter the geometry of silicon-based ceramic nanowires by means of anodic alumina pore size tailoring has been made. However, diverse op...

  16. Quasi-one-dimensional modes in strip plates: Theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Arreola, A.; Báez, G. [Departamento de Ciencias Básicas, Universidad Autónoma Metropolitana-Azcapotzalco, Apartado Postal 21-267, 04000 México Distrito Federal (Mexico); Méndez-Sánchez, R. A. [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico)

    2014-01-14

    Using acoustic resonance spectroscopy we measure the elastic resonances of a strip rectangular plate with all its ends free. The experimental setup consist of a vector network analyzer, a high-fidelity audio amplifier, and electromagnetic-acoustic transducers. The one-dimensional modes are identified from the measured spectra by comparing them with theoretical predictions of compressional and bending modes of the plate modeled as a beam. The agreement between theory and experiment is excellent.

  17. Photoconduction in CDW conductors

    Energy Technology Data Exchange (ETDEWEB)

    Zaitsev-Zotov, S.V., E-mail: serzz@cplire.ru [Kotel' nikov IRE RAS, Mokhovaya 11, Bld. 7, 125009 Moscow (Russian Federation); Minakova, V.E.; Nasretdinova, V.F.; Zybtsev, S.G. [Kotel' nikov IRE RAS, Mokhovaya 11, Bld. 7, 125009 Moscow (Russian Federation)

    2012-06-01

    Photoconduction study of quasi-1D conductors allows to distinguish between the single-particle and collective linear conduction, investigate the effect of screening on collective transport and obtain interesting new details of the electronic energy structure of pure and doped CDW conductors. Here we present results of photoconduction study in quasi-1D conductors o-TaS{sub 3}, K{sub 0.3}MoO{sub 3}, and NbS{sub 3}(I).

  18. Unveiling the microscopic nature of correlated organic conductors: The case of κ-(ET)2Cu[N(CN)2]BrxCl1-x

    Science.gov (United States)

    Ferber, Johannes; Foyevtsova, Kateryna; Jeschke, Harald O.; Valentí, Roser

    2014-05-01

    A few organic conductors show a diversity of exciting properties like Mott insulating behavior, spin liquid, antiferromagnetism, bad metal, or unconventional superconductivity controlled by small changes in temperature, pressure, or chemical substitution. While such a behavior can be technologically relevant for functional switches, a full understanding of its microscopic origin is still lacking and poses a challenge in condensed matter physics since these phases may be a manifestation of electronic correlation. Here we determine from first principles the microscopic nature of the electronic phases in the family of organic systems κ-(ET)2Cu[N(CN)2]BrxCl1-x by a combination of density functional theory calculations and the dynamical mean field theory approach in a form adapted for organic systems. By computing spectral and optical properties we are able to disentangle the origin of the various optical transitions in these materials and prove that correlations are responsible for relevant features. Remarkably, while some transitions are inherently affected by correlations, others are completely uncorrelated. We discuss the consequences of our findings for the phase diagram in these materials.

  19. Exact matrix treatment of an osmotic ensemble model of adsorption and pressure induced structural transitions in metal organic frameworks.

    Science.gov (United States)

    Dunne, Lawrence J; Manos, George

    2016-03-14

    Here we present an exactly treated quasi-one dimensional statistical mechanical osmotic ensemble model of pressure and adsorption induced breathing structural transformations of metal-organic frameworks (MOFs). The treatment uses a transfer matrix method. The model successfully reproduces the gas and pressure induced structural changes which are observed experimentally in MOFs. The model treatment presented here is a significant step towards analytical statistical mechanical treatments of flexible metal-organic frameworks.

  20. A lithium superionic conductor.

    Science.gov (United States)

    Kamaya, Noriaki; Homma, Kenji; Yamakawa, Yuichiro; Hirayama, Masaaki; Kanno, Ryoji; Yonemura, Masao; Kamiyama, Takashi; Kato, Yuki; Hama, Shigenori; Kawamoto, Koji; Mitsui, Akio

    2011-07-31

    Batteries are a key technology in modern society. They are used to power electric and hybrid electric vehicles and to store wind and solar energy in smart grids. Electrochemical devices with high energy and power densities can currently be powered only by batteries with organic liquid electrolytes. However, such batteries require relatively stringent safety precautions, making large-scale systems very complicated and expensive. The application of solid electrolytes is currently limited because they attain practically useful conductivities (10(-2) S cm(-1)) only at 50-80 °C, which is one order of magnitude lower than those of organic liquid electrolytes. Here, we report a lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure. It exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature. This represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes. This new solid-state battery electrolyte has many advantages in terms of device fabrication (facile shaping, patterning and integration), stability (non-volatile), safety (non-explosive) and excellent electrochemical properties (high conductivity and wide potential window).

  1. Structure and physical properties of ternary organic conductors of TCNQ, iodine, and double-charged unsymmetrical cations: PET and PESe

    Energy Technology Data Exchange (ETDEWEB)

    Abashev, G.G. [Perm State Univ. (Russian Federation). Inst. of Natural Sci.; Russkikh, V.S. [Perm State Univ. (Russian Federation). Inst. of Natural Sci.; Koshta, A. [Polska Akademia Nauk, Poznan (Poland). Inst. Fizyki Molekularnej; Lapinski, A. [Polska Akademia Nauk, Poznan (Poland). Inst. Fizyki Molekularnej; Krol, S. [Polska Akademia Nauk, Poznan (Poland). Inst. Fizyki Molekularnej; Pukacki, W. [Polska Akademia Nauk, Poznan (Poland). Inst. Fizyki Molekularnej; Graja, A. [Polska Akademia Nauk, Poznan (Poland). Inst. Fizyki Molekularnej

    1996-01-01

    Ternary organic salts of TCNQ, iodine, and double-charged unsymmetrical cations containing sulfur or selenium are investigated. The crystal structure of the salts is determined; their dc electrical conductivity, ESR, and IR spectral properties are studied. The physical properties of the investigated salts are found as typical for Q-1D organic semiconductors. (orig.)

  2. Uniaxial strain effects on transport properties of a supramolecular organic conductor theta-(DIETS) sub 2 [Au(CN) sub 4

    CERN Document Server

    Tajima, N; Kato, R; Nishio, Y; Kajita, K

    2003-01-01

    Pressure-controlled switching between an insulating state and a superconducting state has been successfully realized on a supramolecular organic conductor theta-(DIETS) sub 2 [Au(CN) sub 4] [DIETS = diiodo(ethylenedithio)diselenadithiafulvalene]. Strong contact between iodine on the donor (DIETS) molecule and nitrogen on the anion [Au(CN) sub 4] genetates characteristic uniaxial strain effects on transport properties. Under the ambient pressure, the present system undergoes a semiconductor-insulator transition at 226 K. The effect of strains parallel to the conduction plane (ab-plane) is very small. Even under uniaxial strains up to 20 kbar along the a- and b-axis directions, the transition is not suppressed. Surprisingly, however, the c-axis strain induces a superconducting state with T sub c of 8.6 K at 10 kbar. Band parameter calculation and the conductivity anisotropy ratio suggest that an increase in the bandwidth W associated with a c-axis strain transforms the system to the metallic and superconducting...

  3. Magnetothermopower study of the charge density wave state in a multiband organic conductor α - (BEDT - TTF)2KHg(SCN)4

    Science.gov (United States)

    Krstovska, Danica

    2017-02-01

    Magnetic field dependence of the thermopower and Nernst effect of the multiband organic conductor α - (BEDT - TTF)2KHg(SCN)4 is theoretically studied at low temperatures in the charge density wave (CDW) state, to fields of 30 T and several field directions. A theoretical model of quantum interlayer tunneling for the q1D charge carriers is used to probe the thermoelectric effects in the CDW state. The contribution from the q2D carriers is calculated by using the Boltzmann transport theory. The background components of the thermopower and Nernst effect as well as the quantum oscillations that originate from the closed Fermi surface orbits are analyzed. The model implies that in the CDW state, the properties of α - (BEDT - TTF)2KHg(SCN)4 are determined mostly by the orbits on the new open Fermi sheets. This is in accord with the previously reported CDW scenario of the low temperature state of α - (BEDT - TTF)2KHg(SCN)4 with imperfect nesting of the open Fermi surface sections.

  4. Spin splitting at the high-magnetic-field phase transition of the organic conductor α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Sasaki, Takahiko; Fukase, Tetsuo

    1999-06-01

    Spin splitting of the de Haas-van Alphen (dHvA) effect is studied in the quasi-two-dimensional organic conductor α-(BEDT-TTF)2KHg(SCN)4 by means of the magnetic torque method. The magnetic field direction dependence of the dHvA oscillation amplitude shows that the spin-splitting zero angles change at 23 T, where the phase transition magnetic field between the low-temperature, low-magnetic-field phase [antiferromagnetic (AF) phase] and the high-magnetic-field phase (M* phase) is. This change implies the increase of the g(mc/m0) value in the AF phase, where g is the g value, mc and m0 the cyclotron effective and free electron masses, respectively. The enhancement of the electron-electron interaction may be the origin of the large g(mc/m0) value in the AF phase. This result supports a model which requires a modification of the Lifshitz-Kosevich formulation in the AF phase in order to evaluate the effective mass and Dingle temperature correctly. In addition, anomalous structures on the magnetic torque curves are observed in both the AF and the M* phases. Each structure may correspond to the subsequent phase transitions by changing the magnetic field direction.

  5. Shubnikov de Haas oscillations and field-induced anomaly in an organic conductor β-(EDO-TTFVO)2FeCl4

    Science.gov (United States)

    Teramura, M.; Yasuzuka, S.; Yoshino, H.; Yokogawa, K.; Sasaki, T.; Fujiwara, H.; Sugimoto, T.; Hiraoka, T.; Hayashi, T.; Murata, Keizo

    2007-03-01

    In order to investigate its electronic structure and the π-d interaction, we studied magnetoresistance (MR) of β″-(EDO-TTFVO) 2FeCl 4. In the course of experiment Shubnikov-de Haas (SdH) effect was found, which shows that this material is a 2D metal. Below 3.5 K (close to TN), MR shows a dip anomaly near 8 T. The anomaly becomes more prominent and shifts slightly to higher field with lowering temperature. The dip anomaly may be caused by the transition from the antiferromagnetic to the paramagnetic states. In addition, SdH oscillations are clearly seen at 0.5 K, whose cross-sectional area corresponds to 13% of the first Brillouin zone. The mass of the π-electrons is m*≃3.3 me, which seems heavy as compared with non-magnetic organic conductors with similar cross-sectional areas, suggesting the enhancement of the mass due to magnetic interaction with the Fe 3d spins.

  6. Correlation Effects on Charge Order and Zero-Gap State in the Organic Conductor α-(BEDT-TTF)2I3

    Science.gov (United States)

    Tanaka, Yasuhiro; Ogata, Masao

    2016-10-01

    The effects of electron correlation in the quasi-two-dimensional organic conductor α-(BEDT-TTF)2I3 are investigated theoretically by using an extended Hubbard model with on-site and nearest-neighbor Coulomb interactions. A variational Monte Carlo method is applied to study its ground-state properties. We show that there appears a nonmagnetic horizontal-stripe charge order in which nearest-neighbor correlation functions indicate a tendency toward a spin-singlet formation on the bonds with large transfer integrals along the charge-rich stripe. Under uniaxial pressure, a first-order transition from the nonmagnetic charge order to a zero-gap state occurs. Our results on a spin correlation length in the charge-ordered state suggest that a spin gap is almost unaffected by the uniaxial pressure in spite of the suppression of the charge disproportionation. The relevance of these contrasting behaviors in spin and charge degrees of freedom to recent experimental observations is discussed.

  7. Doping of Semi Conductors

    Directory of Open Access Journals (Sweden)

    V. V. Agashe

    1960-07-01

    Full Text Available Most of the semi-conductors are formed by addition of foreign substances in an insulator. This is called 'Doping'. These doped semi-conductors today are widely used in many electrical devices. Some of them are rectifiers, transistors, thermistors, oxides cathodes and photo-sensitive elements. This paper reviews the fundamental concept of impurity in semi-conductors and recent work on doping of the latter. Purification methods are described in the case of group IV elements and semi-conducting intermetallic compounds. Results of different physical measurements have been discussed in order to understand the role of 'doping'.

  8. Plasmonic transparent conductors

    Science.gov (United States)

    Liapis, Andreas C.; Sfeir, Matthew Y.; Black, Charles T.

    2016-09-01

    Many of today's technological applications, such as solar cells, light-emitting diodes, displays, and touch screens, require materials that are simultaneously optically transparent and electrically conducting. Here we explore transparent conductors based on the excitation of surface plasmons in nanostructured metal films. We measure both the optical and electrical properties of films perforated with nanometer-scale features and optimize the design parameters in order to maximize optical transmission without sacrificing electrical conductivity. We demonstrate that plasmonic transparent conductors can out-perform indium tin oxide in terms of both their transparency and their conductivity.

  9. 76 FR 69801 - Conductor Certification

    Science.gov (United States)

    2011-11-09

    ... definition of ``conductor'' is a fundamental element of the conductor certification regulation and FRA does... and 219. G. Vision and Hearing Acuity BLET/UTU commented that proposed Sec. 242.117(k) should...

  10. Hydrogen-bond-dynamics-based switching of conductivity and magnetism: a phase transition caused by deuterium and electron transfer in a hydrogen-bonded purely organic conductor crystal.

    Science.gov (United States)

    Ueda, Akira; Yamada, Shota; Isono, Takayuki; Kamo, Hiromichi; Nakao, Akiko; Kumai, Reiji; Nakao, Hironori; Murakami, Youichi; Yamamoto, Kaoru; Nishio, Yutaka; Mori, Hatsumi

    2014-08-27

    A hydrogen bond (H-bond) is one of the most fundamental and important noncovalent interactions in chemistry, biology, physics, and all other molecular sciences. Especially, the dynamics of a proton or a hydrogen atom in the H-bond has attracted increasing attention, because it plays a crucial role in (bio)chemical reactions and some physical properties, such as dielectricity and proton conductivity. Here we report unprecedented H-bond-dynamics-based switching of electrical conductivity and magnetism in a H-bonded purely organic conductor crystal, κ-D3(Cat-EDT-TTF)2 (abbreviated as κ-D). This novel crystal κ-D, a deuterated analogue of κ-H3(Cat-EDT-TTF)2 (abbreviated as κ-H), is composed only of a H-bonded molecular unit, in which two crystallographically equivalent catechol-fused ethylenedithiotetrathiafulvalene (Cat-EDT-TTF) skeletons with a +0.5 charge are linked by a symmetric anionic [O···D···O](-1)-type strong H-bond. Although the deuterated and parent hydrogen systems, κ-D and κ-H, are isostructural paramagnetic semiconductors with a dimer-Mott-type electronic structure at room temperature (space group: C2/c), only κ-D undergoes a phase transition at 185 K, to change to a nonmagnetic insulator with a charge-ordered electronic structure (space group: P1). The X-ray crystal structure analysis demonstrates that this dramatic switching of the electronic structure and physical properties originates from deuterium transfer or displacement within the H-bond accompanied by electron transfer between the Cat-EDT-TTF π-systems, proving that the H-bonded deuterium dynamics and the conducting TTF π-electron are cooperatively coupled. Furthermore, the reason why this unique phase transition occurs only in κ-D is qualitatively discussed in terms of the H/D isotope effect on the H-bond geometry and potential energy curve.

  11. Well Conductor Strain Monitoring

    Science.gov (United States)

    2014-05-06

    comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE JUL 2014 2. REPORT TYPE 3. DATES...849,429; filed on June 26, 2013 by the inventor, Dr. Anthony Ruffa and entitled “ SUBSEA WELL CONDUCTOR STRAIN MONITORING”. STATEMENT OF

  12. Theory of Superionic Conductors

    Science.gov (United States)

    1981-09-01

    TYPE OF REPORT 6 PERIOO COVERED Final Technical )THEORY OF SUPERIONIC CONDUCTORS 9/30/76 to 9/30/81 SVIERFORMI- 4G ORG REPURT NUMBER AI I 1,701 ,- S...several mathematical models of ion and electron conduction in many-particle systems. . DD AN 1473 SECURIT "-CLASSIiCAt N OF THIS PAGE 1 (Wen D E / / A

  13. Structural vs electronic origin of renormalized band widths in TTF-TCNQ: An angular dependent NEXAFS study

    DEFF Research Database (Denmark)

    Sing, M; Meyer, J; Hoinkis, M

    2007-01-01

    We have performed angle-dependent near-edge x-ray absorption fine structure measurements in the Auger electron yield mode on the correlated quasi-one-dimensional organic conductor tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) in order to determine the orientation of the molecules...

  14. The CMS conductor

    CERN Document Server

    Blau, Bertrand; Curé, B; Folch, R; Hervé, A; Horváth, I L; Kircher, F; Musenich, R; Neuenschwander, J; Riboni, P; Seeber, B; Tavares, S; Sgobba, Stefano; Smith, R P

    2002-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. The magnetic field is achieved by means of a four-layer superconducting solenoid. The stored magnetic energy is 2.7 GJ at nominal current of 20 kA (at 4.5 K operating temperature). The coil is wound from a high purity aluminum- stabilized Rutherford type conductor. Unlike other existing Al- stabilized thin solenoids, the structural integrity of the CMS coil is ensured both by the Al-alloy reinforcement welded to the conductor and an external support cylinder. The flat NbTi cable is embedded in high purity aluminum by a continuous co-extrusion process. (7 refs).

  15. Physics of superionic conductors

    CERN Document Server

    1979-01-01

    Superionic conductors are solids whose ionic conductivities approach, and in some cases exceed, those of molten salts and electrolyte solutions. This implies an un­ usual state of matter in which some atoms have nearly liquidlike mobility while others retain their regular crystalline arrangement. This liquid-solid duality has much appeal to condensed matter physicists, and the coincident development of powerful new methods for studying disordered solids and interest in superionic conductors for technical applications has resulted in a new surge of activity in this venerable field. It is the purpose of this book to summarize the current re­ search in the physics of superionic conduction. with special emphasis on those aspects which set these materials apart from other solids. The volume is aimed to­ wards the materials community and will, we expect, stimulate further research on these potentially useful substances. The usual characterization of the superionic phase lists high ionic conductivity; low activat...

  16. Plasmonic Graphene Transparent Conductors

    Science.gov (United States)

    2012-01-01

    www.MaterialsViews.com www.advopticalmat.de FU LL P A P ER Guowei Xu,* Jianwei Liu, Qian Wang , Rongqing Hui, Zhijun Chen, Victor A. Maroni, and Judy Wu Plasmonic...decision, unless so designated by other documentation. 12. DISTRIBUTION AVAILIBILITY STATEMENT Approved for public release; distribution is unlimited. UU...Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS surface plasmon, graphene, transparent conductors Guowei Xu, Jianwei Liu, Qian

  17. The CMS conductor

    CERN Document Server

    Horváth, I L; Marti, H P; Neuenschwander, J; Smith, R P; Fabbricatore, P; Musenich, R; Calvo, A; Campi, D; Curé, B; Desirelli, Alberto; Favre, G; Riboni, P L; Sgobba, Stefano; Tardy, T; Sequeira-Lopes-Tavares, S

    2000-01-01

    The Compact Muon Solenoid (CMS) is one of the experiments, which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN, the design field of the CMS magnet is 4 T, the magnetic length is 13 m and the aperture is 6 m. This high magnetic field is achieved by means of a 4 layer, 5 modules superconducting coil. The coil is wound from an Al-stabilized Rutherford type conductor. The nominal current of the magnet is 20 kA at 4.5 K. In the CMS coil the structural function is ensured, unlike in other existing Al-stabilized thin solenoids, both by the Al-alloy reinforced conductor and the external former. In this paper the retained manufacturing process of the 50-km long reinforced conductor is described. In general the Rutherford type cable is surrounded by high purity aluminium in a continuous co-extrusion process to produce the Insert. Thereafter the reinforcement is joined by Electron Beam Welding to the pure Al of the insert, before being machined to the final dimensions. During the...

  18. Alternative HTS coated conductors

    Science.gov (United States)

    Blaugher, R. D.; Bhattacharya, R. N.; Chen, J.; Padmanabhan, R.

    2002-10-01

    The availability of Bi-2223 high-temperature-superconductor (HTS) powder-in-tube (PIT) tape, with acceptable performance for long lengths, has provided the ability to construct a wide range of HTS electric power components. As a result, there are major worldwide projects in developing HTS electric power components for demonstration in a utility environment. Utility acceptance for superconducting power equipment will depend on several key factors: improved system performance, lower life-cycle costs, higher efficiency versus conventional technology, reliability and maintenance comparable to conventional power equipment, and a competitive installed cost. The latter is impacted by the current high cost of HTS conductors, which must be lowered to costs comparable to conventional Nb-Ti wire, i.e., $2-5/kAm. The present performance and cost of state-of-the-art Bi-2223 HTS tape, although acceptable for prototype construction, is viewed as a major deterrent that may compromise eventual commercialization for most of these electric power devices. The so-called second-generation coated conductor development, with emphasis on conductors employing HTS YBCO films, is viewed as the solution to this performance and cost issue. The potential for the Tl, Hg, and Bi-oxide superconductors for producing an HTS tape as alternatives to Bi-2223 PIT (and YBCO) will be discussed with some recent results on Bi-2212 “coated conductor” development.

  19. Determination of Band-filling Change in the Two-dimensional Organic Conductor, τ-(EDO-S,S-DMEDT-TTF)2(AuBr2)1+y, (y ≤ 0.875) by the Quantum Oscillation of Magnetoresistance

    Science.gov (United States)

    Yoshino, Harukazu; Murata, Keizo; Nakanishi, Tsutomu; Li, Lin; Choi, Eun Sang; Graf, David; Brooks, James S.; Nogami, Yoshio; Papavassiliou, George C.

    2005-01-01

    The effect of thermal treatment on the transport properties is studied for a two-dimensional organic conductor τ-(EDO-S,S-DMEDT-TTF)2(AuBr2)1+y, (y ≤ 0.875). The temperature dependence of the electric resistivity below room temperature was found to be changed from metallic down to low temperature to semiconducting by heating up to 420 K. One of the two frequencies of Shubnikov--de Haas oscillations are found to be different between the non-heated and heated parts from a single crystal, while no evidence of structural change in X-ray photograph was observed. The present result clearly shows that nominal valence or band filling can be controlled by simple thermal treatment for the quasi-two-dimensional organic metal. The mechanism of the change in the band filling is discussed in terms of anion decomposition.

  20. Shubnikov de Haas oscillations in the two-dimensional organic conductor τ-(EDO-S,S-DMEDT- TTF)2(AuBr2)1+y (y˜0.75)

    Science.gov (United States)

    Konoike, Takako; Iwashita, K.; Yoshino, H.; Murata, Keizo; Sasaki, T.; Papavassiliou, G. C.

    2002-12-01

    The quasi-two-dimensional organic τ-type conductor, τ-(EDO-S,S-DMEDT-TTF)2(AuBr2)1+y (y˜0.75), shows metallic temperature dependence of the resistivity down to Tmin˜50 K, below which resistance upturn is observed. There has been no evidence of the phase transition through Tmin. In this work, in pursuit of direct evidence for metal at low temperature by transport measurement, we show an observation of the Shubnikov de Haas (SdH) oscillations for this salt. The observed frequencies of the oscillations are inconsistent with the previous band calculation. Further, it is remarkable that the amplitude of the oscillation was so giant (|Δρ/ρ0|˜30%), and the oscillation above 20 T corresponds to a N=2 Landau state, i.e., next to a quantum limit. We also observed the SdH oscillations in other τ-type conductor, τ-(P-S,S-DMEDT-TTF)2(AuBr2)1+y (y˜0.75), which almost reproduced the previous report by Storr et al. [Phys. Rev. B 64, 045107 (2001)].

  1. Conditioning flat conductors for flat conductor cable production

    Science.gov (United States)

    1968-01-01

    Apparatus can straighten, anneal, clean, and a tension to stretch a cable one percent to assure uniform cross-sectional area. A conductor passes through temperature controlled distilled water and through a toroid coil. As The conductor enters the water, steam performs the cleaning action. Quenching and annealing also take place.

  2. Oxygen ion conductors

    Directory of Open Access Journals (Sweden)

    Stephen J Skinner

    2003-03-01

    A very interesting subgroup of this class of materials are the oxides that display oxygen ion conductivity. As well as the intrinsic interest in these materials, there has been a continued drive for their development because of the promise of important technological devices such as the solid oxide fuel cell (SOFC, oxygen separation membranes, and membranes for the conversion of methane to syngas1. All of these devices offer the potential of enormous commercial and ecological benefits provided suitable high performance materials can be developed. In this article we will review the materials currently under development for application in such devices with particular reference to some of the newly discovered oxide ion conductors.

  3. Solid state proton conductors properties and applications in fuel cells

    CERN Document Server

    Knauth, Philippe

    2012-01-01

    Proton conduction can be found in many different solid materials, from organic polymers at room temperature to inorganic oxides at high temperature. Solid state proton conductors are of central interest for many technological innovations, including hydrogen and humidity sensors, membranes for water electrolyzers and, most importantly, for high-efficiency electrochemical energy conversion in fuel cells. Focusing on fundamentals and physico-chemical properties of solid state proton conductors, topics covered include: Morphology and Structure of Solid Acids Diffusion in Soli

  4. Floating insulated conductors for heating subsurface formations

    Science.gov (United States)

    Burns, David; Goodwin, Charles R.

    2014-07-29

    A heating system for a subsurface formation includes a conduit located in a first opening in the subsurface formation. Three electrical conductors are located in the conduit. A return conductor is located inside the conduit. The return conductor is electrically coupled to the ends of the electrical conductors distal from the surface of the formation. Insulation is located inside the conduit. The insulation electrically insulates the three electrical conductors, the return conductor, and the conduit from each other.

  5. 77 FR 6482 - Conductor Certification

    Science.gov (United States)

    2012-02-08

    ... TRANSPORTATION Federal Railroad Administration 49 CFR Part 242 Conductor Certification AGENCY: Federal Railroad..., published on November 9, 2011, which prescribed regulations for certification of conductors as required by... Certification, U.S. Department of Transportation, Federal Railroad Administration, Mail Stop-25, Room...

  6. Cyclotron resonance and De Haas-Van Alphen effect in (BEDT-TTF) sub 8 Hg sub 4 Cl sub 1 sub 2 (C sub 6 H sub 5 Cl) sub 2 organic conductor

    CERN Document Server

    Voskobojnikov, I B; Samarin, N A; Cluchanko, N E; Lyubovskaya, R N; Moshchalkov, V V

    2002-01-01

    Within 0.33-1.44 K temperature range at B <= 50 T magnetic field values one measured the De Haas-Van Alphen effect for (BEDT-TTF) sub 8 Hg sub 4 Cl sub 1 sub 2 (C sub 6 H sub 5 Cl) sub 2 organic quasi-two-dimensional conductor. Analysis of quantum oscillations with regard to data on cyclotron resonance derived for 40-120 GHz frequency interval enabled to determine that a complex spectrum of quantum oscillations was formed by alpha approx 256 T and beta approx 670-610 T fundamental frequencies as well as, by combination and multiple frequencies. It is shown that nature of temperature rearrangement of oscillation spectrum may be interpreted in terms of model taking account of occurrence of magnetic phase transition at T sub c approx 0.9 K and proximity of a fundamental frequency with m* = 1.48m sub 0 efficient mass to the spin dumping condition

  7. Role of anion size, magnetic moment, and disorder on the properties of the organic conductor {kappa}-(BETS){sub 2}Ga{sub 1-x}Fe{sub x}Cl{sub 4-y}Br{sub y}

    Energy Technology Data Exchange (ETDEWEB)

    Steven, E.; Cui, H.B.; Kismarahardja, A. [Physics Department and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Brooks, J.S., E-mail: brooks@magnet.fsu.ed [Physics Department and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Graf, D. [Physics Department and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Kobayashi, H. [Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-Ku, Tokyo 156-8550 (Japan)

    2010-06-01

    Shubnikov-de Haas and angular dependent magnetoresistance oscillations have been used to explore the role of anion size, magnetic moment, and disorder in the organic conductors {kappa}-(BETS){sub 2}GaBr{sub 4} and {kappa}-(BETS){sub 2}FeCl{sub 2}Br{sub 2} in the isomorphic class {kappa}-(BETS){sub 2}Ga{sub 1-x}Fe{sub x}Cl{sub 4-y}Br{sub y}. The results, combined with previous work, show correlations between the anion composition (Ga{sub 1-x}Fe{sub x}Cl{sub 4-y}Br{sub y}) and the superconducting transition temperature, effective mass, Fermi surface topology, and the mean free path.

  8. High-field phase transitions and Fermi surfaces in the organic conductor α-(BEDT-TTF) 2KHg(SCN) 4: Influence of the magnetic breakdown on evaluation of the effective mass and the scattering time

    Science.gov (United States)

    Sasaki, T.; Biberacher, W.; Fukase, T.

    1998-05-01

    The change of the de Haas-van Alphen (dHvA) oscillation between the low-field spin-density-wave (SDW) phase and the high-field ( H⩾23 T) metallic phase of the organic conductor α-(BEDT-TTF) 2KHg(SCN) 4 is explained in terms of a model of the magnetic breakdown (MB) and a reconstructed Fermi surface by SDW. On the reconstructed Fermi surface, the scattering time obtained by fitting the standard Lifshitz-Kosevich formulation to the dHvA oscillations is affected by the MB giving the additional field-dependent effect. Furthermore, the evaluation of the effective mass needs to consider the additional temperature-dependent factor being due to the MB gap which may change intrinsically and/or thermally with temperature.

  9. Massless Dirac fermions trapping in a quasi-one-dimensional n p n junction of a continuous graphene monolayer

    Science.gov (United States)

    Bai, Ke-Ke; Qiao, Jia-Bin; Jiang, Hua; Liu, Haiwen; He, Lin

    2017-05-01

    Massless Dirac fermions in graphene provide unprecedented opportunities to realize the Klein paradox, which is one of the most exotic and striking properties of relativistic particles. In the seminal theoretical work [M. I. Katsnelson et al., Nat. Phys. 2, 620 (2006), 10.1038/nphys384], it was predicted that the massless Dirac fermions can pass through one-dimensional (1D) potential barriers unimpededly at normal incidence. Such a result seems to preclude confinement of the massless Dirac fermions in graphene by using 1D potential barriers. Here, we demonstrate both experimentally and theoretically that massless Dirac fermions can be trapped in a quasi-1D n p n junction of a continuous graphene monolayer. Because of highly anisotropic transmission of the massless Dirac fermions at n-p junction boundaries (the so-called Klein tunneling in graphene), charge carriers incident at large oblique angles will be reflected from one edge of the junction with high probability and continue to bounce from the opposite edge. Consequently, these electrons are trapped for a finite time to form quasibound states in the quasi-1D n p n junction. The quasibound states seen as pronounced resonances are probed and the quantum interference patterns arising from these states are directly visualized in our scanning tunneling microscope measurements.

  10. Superconductor-insulator transition in quasi-one-dimensional single-crystal Nb₂PdS₅ nanowires.

    Science.gov (United States)

    Ning, Wei; Yu, Hongyan; Liu, Yequn; Han, Yuyan; Wang, Ning; Yang, Jiyong; Du, Haifeng; Zhang, Changjin; Mao, Zhiqiang; Liu, Ying; Tian, Mingliang; Zhang, Yuheng

    2015-02-11

    Superconductor-insulator transition (SIT) in one-dimensional (1D) nanowires attracts great attention in the past decade and remains an open question since contrasting results were reported in nanowires with different morphologies (i.e., granular, polycrystalline, or amorphous) or environments. Nb2PdS5 is a recently discovered low-dimensional superconductor with typical quasi-1D chain structure. By decreasing the wire diameter in the range of 100-300 nm, we observed a clear SIT with a 1D transport character driven by both the cross-sectional area and external magnetic field. We also found that the upper critical magnetic field (Hc2) decreases with the reduction of nanowire cross-sectional area. The temperature dependence of the resistance below Tc can be described by the thermally activated phase slip (TAPS) theory without any signature of quantum phase slips (QPS). These findings demonstrated that the enhanced Coulomb interactions with the shrinkage of the wire diameter competes with the interchain Josephson-like coupling may play a crucial role on the SIT in quasi-1D system.

  11. Magnetic and magnetocaloric properties of quasi-one-dimensional Ising spin chain CoV2O6

    Science.gov (United States)

    Nandi, M.; Mandal, P.

    2016-04-01

    We have investigated the magnetic and magnetocaloric properties of antiferromagnetic Ising spin chain CoV2O6 by magnetization and heat capacity measurements. Both monoclinic α-CoV2O6 and triclinic γ-CoV2O6 exhibit field-induced metamagnetic transitions from antiferromagnetic to ferromagnetic state via an intermediate ferrimagnetic state with 1/3 magnetization plateau. Due to the field-induced metamagnetic transitions, these systems show large conventional as well as inverse magnetocaloric effects. In α-CoV2O6, we observe field-induced complex magnetic phases and multiple magnetization plateaus below 6 K when the field is applied along c axis. Several critical temperatures and fields have been identified from the temperature and field dependence of magnetization, magnetic entropy change, and heat capacity to construct the H-T phase diagram. As compared to α-CoV2O6, γ-CoV2O6 displays a relatively simple magnetic phase diagram. Due to the large magnetic entropy change and adiabatic temperature change at low or moderate applied magnetic field, γ-CoV2O6 may be considered as a magnetic refrigerant in the low-temperature region below 20 K.

  12. Effects of stoichiometry and substitution in quasi-one-dimensional iron chalcogenide BaFe2S3

    Science.gov (United States)

    Hirata, Yasuyuki; Maki, Sachiko; Yamaura, Jun-ichi; Yamauchi, Touru; Ohgushi, Kenya

    2015-11-01

    The effects of off-stoichiometry and elemental substitution on electronic properties of iron-based ladder compound BaFe2S3 are investigated. Resistivity and magnetization are revealed to be quite sensitive to the stoichiometry of Fe atoms, and 10% deficiency at Fe sites reduces the antiferromagnetic transition temperature by 40 K. The antiferromagnetic transition temperature decreases even faster and collapses to zero with hole doping through 10% K substitution at the Ba site, while the antiferromagnetic ordering phase remains with electron doping through 20% Co substitution at the Fe site. Such electron-hole asymmetry is opposite to two-dimensional iron-based superconductors, and can be explained on the basis of both itinerant and localized electronic pictures.

  13. Plane thermonuclear detonation waves initiated by proton beams and quasi-one-dimensional model of fast ignition

    CERN Document Server

    Charakhch'yan, Alexander A

    2014-01-01

    The one-dimensional (1D) problem on bilatiral irradiation by proton beams of the plane layer of condensed DT mixture with length $2H$ and density $\\rho_0 \\leqslant 100\\rho_s$, where $\\rho_s$ is the fuel solid-state density at atmospheric pressure and temperature of 4 K, is considered. The proton kinetic energy is 1 MeV, the beam intensity is $10^{19}$ W/cm$^2$ and duration is 50 ps. A mathematical model is based on the one-fluid two-temperature hydrodynamics with a wide-range equation of state of the fuel, electron and ion heat conduction, DT fusion reaction kinetics, self-radiation of plasma and plasma heating by alpha-particles. If the ignition occurs, a plane detonation wave, which is adjacent to the front of the rarefaction wave, appears. Upon reflection of this detonation wave from the symmetry plane, the flow with the linear velocity profile along the spatial variable $x$ and with a weak dependence of the thermodynamic functions of $x$ occurs. An appropriate solution of the equations of hydrodynamics is...

  14. Magnetic Depopulation of Subbands and Universal Conductance Fluctuations in Quasi-One Dimensional GaAs-AlGaAs Heterostructures

    NARCIS (Netherlands)

    Houten, H. van; Wees, B.J. van; Mooij, J.E.; Roos, G.; Berggren, K.-F.

    1987-01-01

    Narrow conducting channels have been fabricated in the two dimensional electron gas in a GaAs-AlGaAs heterostructure, using a recently developed shallow mesa etch technique. Four terminal high field magnetoresistance measurements at temperatures down to 2 K have been performed on samples with etched

  15. Spin Polarization Oscillations without Spin Precession: Spin-Orbit Entangled Resonances in Quasi-One-Dimensional Spin Transport

    Directory of Open Access Journals (Sweden)

    D. H. Berman

    2014-03-01

    Full Text Available Resonant behavior involving spin-orbit entangled states occurs for spin transport along a narrow channel defined in a two-dimensional electron gas, including an apparent rapid relaxation of the spin polarization for special values of the channel width and applied magnetic field (so-called ballistic spin resonance. A fully quantum-mechanical theory for transport using multiple subbands of the one-dimensional system provides the dependence of the spin density on the applied magnetic field and channel width and position along the channel. We show how the spatially nonoscillating part of the spin density vanishes when the Zeeman energy matches the subband energy splittings. The resonance phenomenon persists in the presence of disorder.

  16. Superconductivity in Ta3Pd3Te14 with quasi-one-dimensional PdTe2 chains.

    Science.gov (United States)

    Jiao, Wen-He; He, Lan-Po; Liu, Yi; Xu, Xiao-Feng; Li, Yu-Ke; Zhang, Chu-Hang; Zhou, Nan; Xu, Zhu-An; Li, Shi-Yan; Cao, Guang-Han

    2016-02-15

    We report bulk superconductivity at 1.0 K in a low-dimensional ternary telluride Ta3Pd3Te14 containing edge-sharing PdTe2 chains along crystallographic b axis, similar to the recently discovered superconductor Ta4Pd3Te16. The electronic heat capacity data show an obvious anomaly at the transition temperature, which indicates bulk superconductivity. The specific-heat jump is ΔC/(γ(n)T(c)) ≈ 1.35, suggesting a weak coupling scenario. By measuring the low-temperature thermal conductivity, we conclude that Ta3Pd3Te14 is very likely a dirty s-wave superconductor. The emergence of superconductivity in Ta3Pd3Te14 with a lower T(c), compared to that of Ta4Pd3Te16, may be attributed to the lower density of states.

  17. Understanding core conductor fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Swenson, D E, E-mail: deswenson@affinity-esd.com [Affinity Static Control Consulting, LLC 2609 Quanah Drive, Round Rock, Texas, 78681 (United States)

    2011-06-23

    ESD Association standard test method ANSI/ESD STM2.1 - Garments (STM2.1), provides electrical resistance test procedures that are applicable for materials and garments that have surface conductive or surface dissipative properties. As has been reported in other papers over the past several years{sup 1} fabrics are now used in many industries for electrostatic control purposes that do not have surface conductive properties and therefore cannot be evaluated using the procedures in STM2.1{sup 2}. A study was conducted to compare surface conductive fabrics with samples of core conductor fibre based fabrics in order to determine differences and similarities with regards to various electrostatic properties. This work will be used to establish a new work item proposal within WG-2, Garments, in the ESD Association Standards Committee in the USA.

  18. Flat conductor cable commercialization project

    Science.gov (United States)

    Hogarth, P.; Wadsworth, E.

    1977-01-01

    An undercarpet flat conductor cable and a baseboard flat conductor cable system were studied for commercialization. The undercarpet system is designed for use in office and commercial buildings. It employs a flat power cable, protected by a grounded metal shield, that terminates in receptacles mounted on the floor. It is designed to interface with a flat conductor cable telephone system. The baseboard system consists of a flat power cable mounted in a plastic raceway; both the raceway and the receptacles are mounted on the surface of the baseboard. It is designed primarily for use in residential buildings, particularly for renovation and concrete and masonry construction.

  19. PREFACE: International Symposium on Molecular Conductors: Novel Functions of Molecular Conductors under Extreme Conditions (ISMC 2008)

    Science.gov (United States)

    Takahashi, Toshihiro; Suzumura, Yoshikazu

    2008-02-01

    The International Symposium on Molecular Conductors 2008 (ISMC2008) was held as the second international symposium of the project entitled `Novel Functions of Molecular Conductors under Extreme Conditions', which was supported by the Grant-in-aid for Scientific Research on Priority Areas from the Ministry of Education, Culture, Sports, Science and Technology in Japan. The project lasted from September 2003 to March 2008, and was completed by this symposium held at Okazaki Conference Center, Institute for Molecular Science, Okazaki, Japan (23-25 July 2008), which about 100 scientists attended. During the symposium, five project teams gave summary talks and exciting talks were given on the topics developed recently not only by the members of the project but also by other scientists including invited speakers from abroad, who are doing active research on molecular conductors. It is expected that papers presented in the symposium will give valuable hints for the next step in the research of this field. Therefore the organizers of this symposium decided to publish this proceedings in order to demonstrate these activities, not only for the local community of the project, but also for the broad society of international scientists who are interested in molecular conductors. The editors, who are also the organizers of this symposium, believe that this proceedings provides a significant and relevant contribution to the field of molecular conductors since it is the first time we have published such a proceedings as an electronic journal. We note that all papers published in this volume of Journal of Physics: Conference Series have been peer reviewed by expert referees. Editors made every effort to satisfy the criterion of a proceedings journal published by IOP Publishing. Toshihiro Takahashi and Yoshikazu Suzumura Editors: Toshihiro Takahashi (Gakushuin University) (Chairman) Kazushi Kanoda (University of Tokyo) Seiichi Kagoshima (University of Tokyo) Takehiko Mori (Tokyo

  20. 33 CFR 183.425 - Conductors: General.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Conductors: General. 183.425... Conductors: General. (a) Each conductor must be insulated, stranded copper. (b) Except for intermittent surges each conductor must not carry a current greater than that specified in Table 5 for the...

  1. 30 CFR 56.12004 - Electrical conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical conductors. 56.12004 Section 56....12004 Electrical conductors. Electrical conductors shall be of a sufficient size and current-carrying... insulating materials. Electrical conductors exposed to mechanical damage shall be protected....

  2. 30 CFR 57.12004 - Electrical conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical conductors. 57.12004 Section 57... Surface and Underground § 57.12004 Electrical conductors. Electrical conductors shall be of a sufficient... operations will not damage the insulating materials. Electrical conductors exposed to mechanical damage...

  3. 33 CFR 183.445 - Conductors: Protection.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Conductors: Protection. 183.445 Section 183.445 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Conductors: Protection. (a) Each conductor or group of conductors that passes through a bulkhead,...

  4. Electromagnetism of rotating conductors revisited

    Energy Technology Data Exchange (ETDEWEB)

    Redzic, Dragan V. [Faculty of Physics, University of Belgrade, Belgrade (Yugoslavia)]. E-mail: redzic@ff.bg.ac.yu

    2002-03-01

    The charge distribution and electromagnetic fields in a rotating, charged conductor under stationary conditions are investigated, assuming that the electrons are at rest relative to the conductor. The basic equations are found, referred to the inertial rest frame of the rotational axis, in the relativistic case, and applied to the case of a cylindrical conductor. The results obtained are compared with those of Groen and Voeyenli (Groen Oe and Voeyenli K 1982 Eur. J. Phys. 3 210-4) who considered the same problem but without taking into account the relative permittivity of the rotating conductor. It is found that the E- and B-fields do not depend on {epsilon}{sub r} and coincide with those calculated by Groen and Voeyenli; the space and surface charge densities, however, depend on {epsilon}{sub r}. (author)

  5. Graphene, a promising transparent conductor

    National Research Council Canada - National Science Library

    Wassei, Jonathan K; Kaner, Richard B

    2010-01-01

    New electronic devices such as touch screens, flexible displays, printable electronics, solid-state lighting and thin film photovoltaics have led to a rapidly growing market for flexible transparent conductors...

  6. Interplay between spin-density wave and 3 d local moments with random exchange in a molecular conductor

    Science.gov (United States)

    Kawaguchi, Genta; Maesato, Mitsuhiko; Komatsu, Tokutaro; Imakubo, Tatsuro; Kitagawa, Hiroshi

    2016-02-01

    We present the results of high-pressure transport measurements on the anion-mixed molecular conductors (DIETSe)2M Br2Cl2 [DIETSe = diiodo(ethylenedithio)tetraselenafulvalene; M =Fe , Ga]. They undergo a metal-insulator (M-I) transition below 9 K at ambient pressure, which is suppressed by applying pressure, indicating a spin-density-wave (SDW) transition caused by a nesting instability of the quasi-one-dimensional (Q1D) Fermi surface, as observed in the parent compounds (DIETSe)2M Cl4 (M =Fe , Ga). In the metallic state, the existence of the Q1D Fermi surface is confirmed by observing the Lebed resonance. The critical pressures of the SDW, Pc, of the M Br2Cl2 (M =Fe , Ga) salts are significantly lower than those of the the M Cl4 (M = Fe, Ga) salts, suggesting chemical pressure effects. Above Pc, field-induced SDW transitions appear, as evidenced by kink structures in the magnetoresistance (MR) in both salts. The FeBr2Cl2 salt also shows antiferromagnetic (AF) ordering of d spins at 4 K, below which significant spin-charge coupling is observed. A large positive MR change up to 150% appears above the spin-flop field at high pressure. At low pressure, in particular below Pc, a dip or kink structure appears in MR at the spin-flop field, which shows unconventionally large hysteresis at low temperature (T hysteresis region clearly decreases with increasing pressure towards Pc, strongly indicating that the coexisting SDW plays an important role in the enhancement of magnetic hysteresis besides the random exchange interaction.

  7. Quartz antenna with hollow conductor

    Science.gov (United States)

    Leung, Ka-Ngo; Benabou, Elie

    2002-01-01

    A radio frequency (RF) antenna for plasma ion sources is formed of a hollow metal conductor tube disposed within a glass tube. The hollow metal tubular conductor has an internal flow channel so that there will be no coolant leakage if the outer glass tube of the antenna breaks. A portion of the RF antenna is formed into a coil; the antenna is used for inductively coupling RF power to a plasma in an ion source chamber. The antenna is made by first inserting the metal tube inside the glass tube, and then forming the glass/metal composite tube into the desired coil shape.

  8. Graphene, a promising transparent conductor

    Directory of Open Access Journals (Sweden)

    Jonathan K. Wassei

    2010-03-01

    Full Text Available New electronic devices such as touch screens, flexible displays, printable electronics, solid-state lighting and thin film photovoltaics have led to a rapidly growing market for flexible transparent conductors. Standard indium tin oxide films are unlikely to satisfy future needs due to losses in conductivity on bending and the escalating cost of indium which is in limited supply. Recent advances in the synthesis and characterization of graphene indicate that it may be suitable for many electronic applications including as a transparent conductor. Graphene hybrids with, for example, carbon nanotubes, may prove to be especially interesting.

  9. Air-Stable n-type Conductors and Semiconductors

    Science.gov (United States)

    2015-07-14

    AFRL-OSR-VA-TR-2015-0209 Air-Stable n-type Conductors and Semiconductors Zhenan Bao LELAND STANFORD JUNIOR UNIVERSITY THE Final Report 07/14/2015...04-2012 to 14-04-2015 4. TITLE AND SUBTITLE Air-Stable n-type Conductors and Semiconductors 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-12-1-0190 5c...2. Design rules and synthesis of high performance n-doped conducting polymers; 3. Fundamental understanding of organic semiconductors through

  10. Improving YBCO Coated Conductors for Applications (Postprint)

    Science.gov (United States)

    2012-02-01

    AFRL-RZ-WP-TP-2012-0123 IMPROVING YBCO COATED CONDUCTORS FOR APPLICATIONS (POSTPRINT) P.N. Barnes, B.C. Harrison, J.W. Kell, and G.A...SUBTITLE IMPROVING YBCO COATED CONDUCTORS FOR APPLICATIONS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...are lighter in weight and smaller in size than their conventional counterparts. The YBCO coated conductor is expected to be the premiere HTS conductor

  11. 46 CFR 111.15-20 - Conductors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Conductors. 111.15-20 Section 111.15-20 Shipping COAST... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-20 Conductors. (a) Each conductor penetration to a battery room must be made watertight. (b) The termination of each...

  12. 33 CFR 159.73 - Conductors.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Conductors. 159.73 Section 159.73 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.73 Conductors. Current carrying conductors must...

  13. 75 FR 69165 - Conductor Certification

    Science.gov (United States)

    2010-11-10

    ... From the Federal Register Online via the Government Publishing Office ] Part II Department of Transportation Federal Railroad Administration 49 CFR Part 242 Conductor Certification; Proposed Rule #0;#0;Federal Register / Vol. 75, No. 217 / Wednesday, November 10, 2010 / Proposed Rules#0;#0; ] DEPARTMENT...

  14. Multicomponent DFT study of geometrical H/D isotope effect on hydrogen-bonded organic conductor, κ-H3(Cat EDT-ST)2

    Science.gov (United States)

    Yamamoto, Kaichi; Kanematsu, Yusuke; Nagashima, Umpei; Ueda, Akira; Mori, Hatsumi; Tachikawa, Masanori

    2017-04-01

    We theoretically investigated a significant contraction of the hydrogen-bonding O⋯O distance upon H/D substitution in our recently developed purely organic crystals, κ-H3(Cat-EDT-ST)2 (H-ST) and its isotopologue κ-D3(Cat-EDT-ST)2 (D-ST), having π-electron systems coupled with hydrogen-bonding fluctuation. The origin of this geometrical H/D isotope effect was elucidated by using the multicomponent DFT method, which takes the H/D nuclear quantum effect into account. The optimized O⋯O distance in H-ST was found to be longer than that in D-ST due to the anharmonicity of the potential energy curve along the Osbnd H bond direction, which was in reasonable agreement with the experimental trend.

  15. Temperature limited heater utilizing non-ferromagnetic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar,; Harold J. (Bellaire, TX), Harris; Kelvin, Christopher [Houston, TX

    2012-07-17

    A heater is described. The heater includes a ferromagnetic conductor and an electrical conductor electrically coupled to the ferromagnetic conductor. The ferromagnetic conductor is positioned relative to the electrical conductor such that an electromagnetic field produced by time-varying current flow in the ferromagnetic conductor confines a majority of the flow of the electrical current to the electrical conductor at temperatures below or near a selected temperature.

  16. Method for making conductors for ferrite memory arrays. [from pre-formed metal conductors

    Science.gov (United States)

    Heckler, C. H.; Baba, P. D.; Bhiwandker, N. C. (Inventor)

    1974-01-01

    The ferrite memory arrays are made from pre-formed metal conductors for the ferrite arrays. The conductors are made by forming a thin sheet of a metallizing paste of metal alloy powder, drying the paste layer, bisque firing the dried sheet at a first temperature, and then punching the conductors from the fired sheet. During the bisque firing, the conductor sheet shrinks to 58 percent of its pre-fired volume and the alloy particles sinter together. The conductors are embedded in ferrite sheet material and finally fired at a second higher temperature during which firing the conductors shrink approximately the same degree as the ferrite material.

  17. Composite conductor containing superconductive wires

    Energy Technology Data Exchange (ETDEWEB)

    Larson, W.L.; Wong, J.

    1974-03-26

    A superconductor cable substitute made by coworking multiple rods of superconductive niobium--titanium or niobium--zirconium alloy with a common copper matrix to extend the copper and rods to form a final elongated product which has superconductive wires distributed in a reduced cross-section copper conductor with a complete metallurgical bond between the normal-conductive copper and the superconductor wires contained therein is described. The superconductor cable can be in the form of a tube.

  18. 46 CFR 111.05-31 - Grounding conductors for systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Grounding conductors for systems. 111.05-31 Section 111... Grounding conductors for systems. (a) A conductor for grounding a direct-current system must be the larger of: (1) The largest conductor supplying the system; or (2) No. 8 AWG (8.4mm2). (b) A conductor...

  19. Effect of Conductor Verbalization, Dynamic Markings, Conductor Gesture, and Choir Dynamic Level on Singers' Dynamic Responses.

    Science.gov (United States)

    Skadsem, Julie A.

    1997-01-01

    Examines the effects of conductor verbalization, dynamic markings, conductor gesture, and choir dynamic level on individual singers' dynamic responses. Indicates that verbal instructions from the conductor elicited significantly stronger dynamic performance responses than did the other instructional conditions. Suggests that additional research…

  20. Responsabilidad penal del conductor ebrio

    OpenAIRE

    Gamboa Mosquera, Mauricio

    2012-01-01

    Mediante el presente artículo se busca mostrar cómo la Corte Suprema de Justicia, en aplicación de la teoría citada ut supra: determinación optativa o alternativa , ha debido aplicar por favorabilidad la condena del conductor a título de homicidio culposo, como quiera que con los mismos elementos de juicio utilizados para concluir que se actuó con dolo eventual, se ha podido arribar al delito imprudente, esto es, al comportamiento culposo.

  1. Guo Shuang, A Woman Conductor

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    BORN in a musical family in Beijing, Guo Shuang began to show her talent for music when she was nine years old and began to learn piano from her mother. At the primary and then the secondary school attached to the Central Conservatory of Music, Guo Shuang studied piano, musical theory and composing. Later, she enrolled in the Conservatory to study conducting and piano under the famous conductors Zheng Xiaoying and Xu Xin, piano professors Wu Ying and Xie Huazhen. In 1989, she went to Germany

  2. Performance analysis of the Nb-Ti conductor qualification samples for the ITER project

    Science.gov (United States)

    Breschi, M.; Carati, D.; Bessette, D.; Devred, A.; Romano, G.; Vostner, A.; Zhou, C.

    2015-11-01

    The ITER machine will require approximately 275 tons of Nb-Ti strands that will be used in poloidal field (PF) coils, correction coils (CC) and feeder busbars. The performance of all these conductors for the ITER machine is qualified by a short full-size sample (4 m) current sharing temperature (T cs) test in the SULTAN facility at CRPP in Villigen, Switzerland, at the design operating current and peak field. Three ITER domestic agencies participated in PF conductor fabrication (China, the European Union, Russia) while the conductors for feeder busbars and correction coils are entirely produced by the Chinese domestic agency. Each conductor type was qualified by the ITER International Organization after reaching T cs values in excess of ITER specifications. This qualification enabled the launch of procurement and industrial production of the Nb-Ti cable-in-conduit conductors in each domestic agency. In this paper, we summarize the performance of the qualified Nb-Ti samples of the ITER Project, comparing strand performance with conductor performance. The details of the test results will be discussed in terms of dc performance, ac losses and minimum quench energies of each conductor type.

  3. Solid-state proton conductors

    Energy Technology Data Exchange (ETDEWEB)

    Jewulski, J.R.; Osif, T.L.; Remick, R.J.

    1990-12-01

    The purpose of this program was to survey the field of solid-state proton conductors (SSPC), identify conductors that could be used to develop solid-state fuel cells suitable for use with coal derived fuel gases, and begin the experimental research required for the development of these fuel cells. This document covers the following topics: the history of developments and current status of the SSPC, including a review of proton conducting electrolyte structures, the current status of the medium temperature SSPC development, electrodes for moderate temperature (SSPC) fuel cell, basic material and measurement techniques applicable for SSPC development, modeling and optimization studies. Correlation and optimization studies, to include correlation studies on proton conduction and oxide cathode optimization for the SSPC fuel cell. Experiments with the SSPC fuel cells including the fabrication of the electrolyte disks, apparatus for conducting measurements, the strontium-cerium based electrolyte, the barium-cerium based electrolyte with solid foil electrodes, the barium-cerium based electrolyte with porous electrodes, and conduction mechanisms. 164 refs., 27 figs., 13 tabs.

  4. Solid-state proton conductors

    Energy Technology Data Exchange (ETDEWEB)

    Remick, R.J.; Jewulski, J.; Osif, T.

    1989-01-01

    Work on this project is divided into three tasks. In the first, a comprehensive literature review was performed for the purpose of collecting data on solid proton conductors. The data was then analyzed with the goal of correlating physical and chemical characteristics with protonic conductivity in order to gain a better understanding of the phenomenon. In the second task, the results of the correlation study were used to choose an electrolyte system in which to work and to aid in the formulation of new candidate proton conductors. Under the third task, a universal test stand was constructed which can measure both electronic and protonic conductivity and which can be converted to use as a solid state fuel cell test stand. Samples of doped SrCe{sub 0.95}Yb{sub 0.05}O{sub 3} have been coated with palladium electrodes and the mechanism responsible for ionic conductivity through this material is currently under study. 6 refs., 1 fig.

  5. Solid-state proton conductors

    Science.gov (United States)

    Jewulski, J. R.; Osif, T. L.; Remick, R. J.

    1990-12-01

    The purpose of this program was to survey the field of solid-state proton conductors (SSPC), identify conductors that could be used to develop solid-state fuel cells suitable for use with coal derived fuel gases, and begin the experimental research required for the development of these fuel cells. This document covers the following topics: the history of developments and current status of the SSPC, including a review of proton conducting electrolyte structures, the current status of the medium temperature SSPC development, electrodes for moderate temperature (SSPC) fuel cell, basic material and measurement techniques applicable for SSPC development, modeling, and optimization studies. Correlation and optimization studies are described which include correlation studies on proton conduction and oxide cathode optimization for the SSPC fuel cell. Experiments with the SSPC fuel cells are presented which include the fabrication of the electrolyte disks, apparatus for conducting measurements, the strontium-cerium based electrolyte, the barium-cerium based electrolyte with solid foil electrodes, the barium-cerium based electrolyte with porous electrodes, and conduction mechanisms.

  6. Assessment of sodium conductor distribution cable

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-06-01

    The study assesses the barriers and incentives for using sodium conductor distribution cable. The assessment considers environmental, safety, energy conservation, electrical performance and economic factors. Along with all of these factors considered in the assessment, the sodium distribution cable system is compared to the present day alternative - an aluminum conductor system. (TFD)

  7. Doped LZO buffer layers for laminated conductors

    Science.gov (United States)

    Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

    2010-03-23

    A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

  8. Assessment of the noise annoyance among subway train conductors in Tehran, Iran.

    Science.gov (United States)

    Hamidi, Mansoureh; Kavousi, Amir; Zaheri, Somayeh; Hamadani, Abolfazl; Mirkazemi, Roksana

    2014-01-01

    Subway transportation system is a new phenomenon in Iran. Noise annoyance interferes with the individual's task performance, and the required alertness in the driving of subway trains. This is the first study conducted to measure the level of noise and noise annoyance among conductors of subway organization in Tehran, Iran. This cross sectional study was conducted among 167 randomly selected train conductors. Information related to noise annoyance was collected by using a self-administered questionnaire. The dosimetry and sound metering was done for the conductors and inside the cabins. There were 41 sound metering measuring samples inside the conductors' cabin, and there were 12 samples of conductors' noise exposure. The results of sound level meter showed that the mean Leq was 73.0 dBA ± 8.7 dBA and the dosimetry mean measured Leq was 82.1 dBA ± 6.8 dBA. 80% of conductors were very annoyed/annoyed by noise in their work place. 53.9% of conductors reported that noise affected their work performance and 63.5% reported that noise causes that they lose their concentration. The noise related to movement of train wheels on rail was reported as the worst by 83.2% followed by the noise of brakes (74.3%) and the ventilation noise (71.9%). 56.9% of conductors reported that they are suffering from sleeplessness, 40.1% from tinnitus and 80.2% feeling fatigue and sleepy. The study results showed the high level of noise and noise annoyance among train conductors and the poor health outcome of their exposure to this level of noise.

  9. Frequency Dependent Losses in Transmission Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdóttir, Unnur Stella

    2011-01-01

    , such as thermal conditions in and around the cable, as well as the heat generated in conductors, screens, armours etc., taking into account proximity and skin effects. The work performed and presented in this paper is concerned with an improved determination of the losses generated in the conductor, by means...... of better calculation of the AC resistance of transmission cable conductors, in particular regarding higher frequencies. In this way, also losses under harmonics can be covered. Furthermore, the model is suitable for modelling of transient attenuation in high voltage cables. The AC resistance is calculated...

  10. 33 CFR 159.71 - Electrical controls and conductors.

    Science.gov (United States)

    2010-07-01

    ... conductors. 159.71 Section 159.71 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Electrical controls and conductors. Electrical controls and conductors must be installed in accordance with good marine practice. Wire must be copper and must be stranded. Electrical controls and conductors...

  11. 30 CFR 56.12011 - High-potential electrical conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-potential electrical conductors. 56.12011... § 56.12011 High-potential electrical conductors. High-potential electrical conductors shall be covered, insulated, or placed to prevent contact with low potential conductors....

  12. 30 CFR 57.12011 - High-potential electrical conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-potential electrical conductors. 57.12011... Electricity Surface and Underground § 57.12011 High-potential electrical conductors. High-potential electrical conductors shall be covered, insulated, or placed to prevent contact with low potential conductors....

  13. 30 CFR 57.12080 - Bare conductor guards.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bare conductor guards. 57.12080 Section 57... Underground Only § 57.12080 Bare conductor guards. Trolley wires and bare power conductors shall be guarded at... conductors are less than 7 feet above the rail, they shall be guarded at all points where persons work...

  14. 46 CFR 111.60-4 - Minimum cable conductor size.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4...-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-4 Minimum cable conductor size. Each cable conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must...

  15. An Exploratory Comparison of Novice, Intermediate, and Expert Orchestral Conductors

    Science.gov (United States)

    Bergee, Martin J.

    2005-01-01

    This study compared novice, "intermediate" (graduate student), and expert orchestral conductors. Two novice conductors, one graduate student in orchestral conducting, and one expert conductor led a university symphony orchestra in part of the first movement of Brahms's Symphony No. 2. Wired for sound, conductors attempted to verbalize their…

  16. 46 CFR 111.50-3 - Protection of conductors.

    Science.gov (United States)

    2010-10-01

    ... conductor must be protected in accordance with its current carrying capacity, except a conductor for the..., Subpart 111.30. (c) Fuses and circuitbreakers. If the allowable current-carrying capacity of the conductor... current-carrying capacity of the conductor; and (2) The effect of temperature on the operation of...

  17. Materiales conductores mediante funcionalización de polímeros con nanomateriales conductores

    OpenAIRE

    Gutierrez, Manuel; Llobera, Andreu; Fernández Sánchez, César; Jiménez Jorquera, Cecilia; Mendoza Gómez, Ernest

    2010-01-01

    La presente invención se refiere un material conductor que comprende un polímero funcionalizado y a un nanomaterial conductor unidos mediante enlace covalente. La invención también se refiere a un procedimiento de obtención del material conductor sin modificar las propiedades ópticas del polímero y a su uso para la fabricación de sensores o electrodos.

  18. Materiales conductores mediante funcionalización de polímeros con nanomateriales conductores

    OpenAIRE

    Gutierrez, Manuel; Llobera, Andreu; Fernández Sánchez, César; Jiménez Jorquera, Cecilia; Mendoza Gómez, Ernest

    2010-01-01

    La presente invención se refiere un material conductor que comprende un polímero funcionalizado y a un nanomaterial conductor unidos mediante enlace covalente. La invención también se refiere a un procedimiento de obtención del material conductor sin modificar las propiedades ópticas del polímero y a su uso para la fabricación de sensores o electrodos.

  19. Failure Mechanism of Reflow Conductor Roll of Electroplating Tinning Line

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The surface roughness of reflow conductor roll was checked on membrane sample. The surface morphology of conductor roll was observed by microscope, and the composition of adhered layer on conductor roll surface was analyzed by X-ray spectroscope. The results show that tin adhesion is the main reason for failure of conductor roll, and the failure of conductor roll is accelerated by wear. The measures to decrease tin adhesion and improve wear resistance were put forward.

  20. Application of protonic conductors in metallurgy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two types of disposable EMF hydrogen sensors for measurements of solute contents of liquid metals in situ in metal-refining processes and their general principles are introduced. The way to design new electrochemical sensors and the direction to develop new protonic conductors as new electrochemical sensors are discussed. The feasibility of protonic conductors worked as hydrogen pump in non-ferrous metal refining processes is discussed as well.

  1. Controlled Electronic Transport through Branched Molecular Conductors

    OpenAIRE

    2008-01-01

    Abstract The conductance through a branched conductor placed between two electrodes is analyzed using the Landauer transport formulation within the framework of the single electron, and the tight binding approximations. Terminal side chains are expressed as self energy terms which map the branched conductor onto an effective linear chain Hamiltonian. The effect of uniform side branches on resonant zero-bias conductance is shown to be analytically solvable and particularly simple, w...

  2. Analysis and application of transmission line conductors

    Science.gov (United States)

    Laney, Orin

    Skin effect is usually a concern reserved for radio frequency design and for high current conductors used in utility power distribution. Proximity effect between adjacent conductors has traditionally been a concern for the design of magnetic windings and other applications involving wire bundles. The rise in the ubiquity of high speed bit streams and other signals of very wide bandwidth has broadened the range of applicable contexts and increased the need to account for such effects. This is especially true for transmission lines used to interconnect critical signal paths in applications ranging from microelectronic devices to the signal integrity of printed circuit traces and implementation of system cabling. Optimal conductor design is obviously fundamental to transmission line performance. Researchers have paid considerable attention to the topic but the results are scattered throughout the literature. This thesis collected information on extant conductor designs, and the theoretical considerations behind each solution. A detailed analysis of current flow in a conducting half-space was included as a foundation. The conductor types discussed were solid cylindrical, rectangular, ribbonoid, bimetallic, tubular, laminated, litz, and stranded constructions. Discussions of the performance of stranded shields and conductor roughness e¤ects were included for completeness of understanding.

  3. Angle-dependent magnetoresistance oscillations in the quasi-two-dimensional organic conductor α-(BEDT- TTF)2NH4Hg(SCN)4: Origin of the difference in ground state between α-(BEDT- TTF)2NH4Hg(SCN)4 and α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Hanasaki, N.; Kagoshima, S.; Miura, N.; Saito, G.

    2001-06-01

    We studied the difference between the ground states of α-(BEDT-TTF)2NH4Hg(SCN)4 and its isostructural compound α-(BEDT-TTF)2KHg(SCN)4 by measuring angle-dependent magnetoresistance. In the NH4 compound, we found resistance minima due to the Lebed resonances. These findings suggest the presence of the one-dimensional Fermi surface parallel to the b*c* plane. Detailed analyses of these resistance minima suggest a large warp in the planarlike Fermi surface along the c* axis. Second and higher harmonic components are necessary to describe the warping of the Fermi surface. We also analyzed the small closed-orbit effect, that is, the peak structure in the resistance for the magnetic field nearly parallel to the conducting plane. It was found that the corrugation in the Fermi surface perpendicular to the a*c* plane was also large in the NH4 compound compared to the K compound. We conclude that such large warps in the Fermi surface suppressed the nesting of the quasi-one-dimensional Fermi surface in the NH4 compound.

  4. The Contribution of the Nickel Subsystem into Magnetic Properties of Quasi One-Dimensional Magnets (Y_{1-{x}} Ndx)2BaNiO5

    Science.gov (United States)

    Popova, E. A.; Klimin, S. A.; Popova, M. N.; Vasiliev, A. N.

    2016-12-01

    Magnetic properties of (Y_{1{-}x}Nd_{{x}})2BaNiO_{5 } with x = 1; 0.25; 0.15; and 0.04 are investigated by means of specific heat, magnetic susceptibility, and spectroscopic measurements. We estimate a magnetic contribution of the neodymium subsystem into a total specific heat and magnetic susceptibility using spectroscopic data. We show that the nickel subsystem is intrinsically disordered in the whole temperature range studied, whereas the magnetization of the nickel chain segments contributes to the total magnetic susceptibility and specific heat at low temperatures.

  5. Modulation of Spin Distribution and Spin Transport by a Magnetic Field in a Quasi-One-Dimensional System with Spin-Orbit Coupling

    Institute of Scientific and Technical Information of China (English)

    LING Dong-Bo; XIA Ke; LI Ding-Ping; MA Zhong-shui

    2006-01-01

    The distributions of spin and currents modulated by magnetic field in a transverse parabolic confined two-dimensional electronic system with a Rashba spin-orbit coupling have been studied numerically.It is shown that the spin accumulation and the spin related current are generated by magnetic field if the spln-orbit coupnng is presented.The distributions of charge and spin currents are antisymmetrical along the cross-section of confined system.A transversely applied electric field does not influence the characteristic behaviour of charge-and spin-dependent properties.

  6. Quasi-one-dimensional polaronic states due to the preferential reduction in the Li sub 1 sub + sub x V sub 3 O sub 8 insertion electrode

    CERN Document Server

    Onoda, M

    2003-01-01

    The structural and electronic properties of the Li sub 1 sub + sub x V sub 3 O sub 8 insertion electrode, where 0 sup 0.1 with nearly stoichiometric oxygen atoms, small polarons exist without carrier-creation energy at high temperatures, while at low temperatures the conduction may be of variable-range hopping (VRH) type. For x > 0.2, one-dimensional magnetic properties appear due to sizable exchange couplings and order-disorder effects of additional Li ions may lead to significant change of transport properties. For the intermediate composition 0 < x sup<= 0.1, strong randomness of the Li doping and the congenital oxygen deficiency cause VRH states even at high temperatures.

  7. LT-STRUCTURAL CHANGES OF THE (NBSE4)10I3 COMPOUND, A QUASI-ONE-DIMENSIONAL CHARGE-DENSITY-WAVE SYSTEM

    NARCIS (Netherlands)

    VUCIC, Z; MEETSMA, A; DEBOER, JL

    1993-01-01

    In order to study the structural background of the giant thermal hysteresis observed in the thermopower measurements [1] of the CDW system (NbSe4)10I3, zeroth-order Weissenberg and oscillation photographs were taken at temperatures below Peierls transition. A reversible transformation of the room te

  8. Neutron diffraction study of quasi-one-dimensional spin-chain compounds Ca3Co2−FeO6

    Indian Academy of Sciences (India)

    Anil Jain; S M Yusuf; Sher Singh

    2008-11-01

    We report the results of the DC magnetization, neutron powder diffraction and neutron depolarization studies on the spin-chain compounds Ca3Co2−FeO6 ( = 0, 0.1, 0.2 and 0.4). Rietveld refinement of neutron powder diffraction patterns at room temperature confirms the single-phase formation for all the compounds in rhombohedral structure with space group R$\\bar{3}$c. Rietveld refinement also confirms that Fe was doped at the trigonal prism site, 6a (0, 0, 1/4) of Co. The high temperature magnetic susceptibility obeys the Curie–Weiss law; the value of the paramagnetic Curie temperature () decreases as the concentration of iron increases and it becomes negative for = 0.4. No extra Bragg peak as well as no observable enhancement in the intensity of the fundamental (nuclear) Bragg peaks has been observed in the neutron diffraction patterns down to 30 K. No depolarization of neutron beam has been observed down to 3 K confirming the absence of ferro- or ferrimagnetic-like correlation.

  9. Phonon States and Dispersive Spectra of Polar Optical Phonons in Quasi-One-Dimensional Nanowires of Wurtzite ZnO and Zinc-Blend MgO Semiconductors*

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li

    2011-01-01

    Within the framework of the macroscopic dielectric continuum model and Loudon's uniaxial crystal model,the phonon modes of a wurtzite/zinc-blende one-dimensional (ID) cylindrical nanowire (NW) are derived and studied.The analytical phonon states of phonon modes are given.It is found that there exist two types of polar phonon modes,i.e.interface optical (IO) phonon modes and the quasi-confined (QC) phonon modes existing in 1D wurtzite/zinc-blende NWs.Via the standard procedure of field quantization, the Frohlich electron-phonon interaction Hamiltonians are obtained.Numerical calculations of dispersive behavior of these phonon modes on a wurtzite/zinc-blende ZnO/MgO NW are performed.The frequency ranges of the I0 and QC phonon modes of the ZnO/MgO NWs are analyzed and discussed.It is found that the IO modes only exist in one frequency range, while QC modes may appear in three frequency ranges.The dispersive properties of the IO and QC modes on the free wave-number kz and the azimuthal quantum number m are discussed.The analytical Hamiltonians of electron-phonon interaction obtained here are quite useful for further investigating phonon influence on optoelectronics properties of wurtzite/zinc-blende 1D NW structures.

  10. Heat transfer and fluid flow of blood with nanoparticles through porous vessels in a magnetic field: A quasi-one dimensional analytical approach.

    Science.gov (United States)

    Rahbari, A; Fakour, M; Hamzehnezhad, A; Vakilabadi, M Akbari; Ganji, D D

    2017-01-01

    In the present study, the analytical study on blood flow containing nanoparticles through porous blood vessels is done in presence of magnetic field using Homotopy Perturbation Method (HPM). Blood is considered as the third grade non- Newtonian fluid containing nanoparticles. Viscosity of nanofluid is determined by Constant, Reynolds' and Vogel's models. Some efforts have been made to show the reliability and performance of the present method compared with the numerical method, Runge-Kutta fourth-order. The results reveal that the HPM can achieve suitable results in predicting the solution of these problems. Moreover, the influence of some physical parameters such as pressure gradient, Brownian motion parameter, thermophoresis parameter, magnetic filed intensity and Grashof number on temperature, velocity and nanoparticles concentration profiles is declared in this research. The results reveal that the increase in the pressure gradient and Thermophoresis parameter as well as decrease in the Brownian motion parameter cause the rise in the velocity profile. Furthermore, either increase in Thermophoresis or decrease in Brownian motion parameters results in enhancement in nanoparticle concentration. The highest value of velocity is observed when the Vogel's Model is used for viscosity. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Quasi-one-dimensional waves in rodent populations in heterogeneous habitats: a consequence of elevational gradients on spatio-temporal dynamics.

    Science.gov (United States)

    Abramson, Guillermo; Giuggioli, Luca; Parmenter, Robert R; Kenkre, V M

    2013-02-21

    Wave propagation can be clearly discerned in data collected on mouse populations in the Cibola National Forest (New Mexico, USA) related to seasonal changes. During an exploration of the construction of a methodology for investigations of the spread of the Hantavirus epidemic in mice we have built a system of interacting reaction diffusion equations of the Fisher-Kolmogorov-Petrovskii-Piskunov type. Although that approach has met with clear success recently in explaining Hantavirus refugia and other spatiotemporal correlations, we have discovered that certain observed features of the wave propagation observed in the data we mention are impossible to explain unless modifications are made. However, we have found that it is possible to provide a tentative explanation/description of the observations on the basis of an assumed Allee effect proposed to exist in the dynamics. Such incorporation of the Allee effect has been found useful in several of our recent investigations both of population dynamics and pattern formation and appears to be natural to the observed system. We report on our investigation of the observations with our extended theory.

  12. Kinetic arrest of field-temperature induced first order phase transition in quasi-one dimensional spin system Ca3Co2O6

    Science.gov (United States)

    De, Santanu; Kumar, Kranti; Banerjee, A.; Chaddah, P.

    2016-05-01

    We have found that the geometrically frustrated spin chain compound Ca3Co2O6 belonging to Ising like universality class with uniaxial anisotropy shows kinetic arrest of first order intermediate phase (IP) to ferrimagnetic (FIM) transition. In this system, dc magnetization measurements followed by different protocols suggest the coexistence of high temperature IP with equilibrium FIM phase in low temperature. Formation of metastable state due to hindered first order transition has also been probed through cooling and heating in unequal field (CHUF) protocol. Kinetically arrested high temperature IP appears to persist down to almost the spin freezing temperature in this system.

  13. Tight-binding chains with off-diagonal disorder: Bands of extended electronic states induced by minimal quasi-one-dimensionality

    Science.gov (United States)

    Nandy, Atanu; Pal, Biplab; Chakrabarti, Arunava

    2016-08-01

    It is shown that an entire class of off-diagonally disordered linear lattices composed of two basic building blocks and described within a tight-binding model can be tailored to generate absolutely continuous energy bands. It can be achieved if linear atomic clusters of an appropriate size are side-coupled to a suitable subset of sites in the backbone, and if the nearest-neighbor hopping integrals, in the backbone and in the side-coupled cluster, bear a certain ratio. We work out the precise relationship between the number of atoms in one of the building blocks in the backbone and that in the side attachment. In addition, we also evaluate the definite correlation between the numerical values of the hopping integrals at different subsections of the chain, that can convert an otherwise point spectrum (or a singular continuous one for deterministically disordered lattices) with exponentially (or power law) localized eigenfunctions to an absolutely continuous spectrum comprising one or more bands (subbands) populated by extended, totally transparent eigenstates. The results, which are analytically exact, put forward a non-trivial variation of the Anderson localization (Anderson P. W., Phys. Rev., 109 (1958) 1492), pointing towards its unusual sensitivity to the numerical values of the system parameters and, go well beyond the other related models such as the Random Dimer Model (RDM) (Dunlap D. H. et al., Phys. Rev. Lett., 65 (1990) 88).

  14. Effects of Conductor Baton Use on Band and Choral Musicians' Perceptions of Conductor Expressivity and Clarity

    Science.gov (United States)

    Nápoles, Jessica; Silvey, Brian A.

    2017-01-01

    The purpose of this study was to examine participants' (college band and choral musicians, N = 143) perceptions of conductor clarity and expressivity after viewing band and choral directors conducting with or without a baton. One band and one choral conductor each prepared and conducted two excerpts of Guy Forbes's "O Nata Lux", a piece…

  15. Conductor fatigue-life research. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, G.E.

    1981-07-01

    This is the final report of Research Project RP 1278-1 sponsored by the Electric Power Research Institute and carried out at the Civil Engineering Department of Auburn University (Auburn, Alabama). The objective of this study was to evaluate the effects of reducing vibration amplitudes of ACSR conductors which had been minimally damaged by aeolian vibration. The aeolian vibration was simulated by mechanical means in a controlled laboratory situation and the reduction in vibration amplitudes was a simulation of the addition of amplitude limiting devices (dampers). Conductors were vibrated at high amplitudes until a predetermined number of strand breaks occurred, after which the vibration was continued at reduced amplitudes. Three different ACSB conductors were tested: 795 KCM 26/7, 795 KCM 45/7, and 397.5 KCM 26/7. These conductors were chosen to establish the effects of conductor size and stranding on the amplitude reduction tests. Two different amplitude reductions were used to establish a threshold value for a maximum reduced amplitude. Previous preliminary research by others indicated that amplitude reductions extended the working life of conductors. This research expanded the amplitude reduction values and conductor sizes and strandings tested. For each set of parameters, four duplicative tests were performed to give statistical credence to the data. The results of the investigation indicated that amplitude reductions arrested fatigue strand breakage in each case. Electric utilities can utilize the results of this EPRI project in assessing the fatigue life of minimally damaged transmisson lines and in evaluating techniques for mitigating fatigue damage.

  16. Tunable Broadband Printed Carbon Transparent Conductor

    Science.gov (United States)

    Xu, Yue; Wan, Jiayu

    Transparent conductors have been widely applied in solar cells, transparent smart skins, and sensing/imaging antennas, etc. Carbon-based transparent conductor has attracted great attention for its low cost and broad range transparency. Ion intercalation has been known to highly dope graphitic materials, thereby tuning materials' optoelectronic properties. For the first time, we successfully tune the optical transmittance of a reduced graphene oxide (RGO)/CNT network from mid-IR range to visible range by means of Li-ion intercalation/deintercalation. We also observed a simultaneous increase of the electrical conductivity with the Li-ion intercalation. This printed carbon hybrid thin film was prepared through all solution processes and was easily scalable. This study demonstrates the possibility of using ion intercalation for low cost, tunable broadband transparent conductors.

  17. Properties and applications of perovskite proton conductors

    Directory of Open Access Journals (Sweden)

    Eduardo Caetano Camilo de Souza

    2010-09-01

    Full Text Available A brief overview is given of the main types and principles of solid-state proton conductors with perovskite structure. Their properties are summarized in terms of the defect chemistry, proton transport and chemical stability. A good understanding of these subjects allows the manufacturing of compounds with the desired electrical properties, for application in renewable and sustainable energy devices. A few trends and highlights of the scientific advances are given for some classes of protonic conductors. Recent results and future prospect about these compounds are also evaluated. The high proton conductivity of barium cerate and zirconate based electrolytes lately reported in the literature has taken these compounds to a highlight position among the most studied conductor ceramic materials.

  18. Measuring the Magnetic Force on a Current-Carrying Conductor.

    Science.gov (United States)

    Herreman, W.; Huysentruyt, R.

    1995-01-01

    Describes a fast and simple method for measuring the magnetic force acting on a current-carrying conductor using a digital balance. Discusses the influence of current intensity and wire length on the magnetic force on the conductor. (JRH)

  19. Fragmented carbon nanotube macrofilms as adhesive conductors for lithium-ion batteries.

    Science.gov (United States)

    Cao, Zeyuan; Wei, Bingqing

    2014-03-25

    Polymer binders such as poly(vinylidene fluoride) (PVDF) and conductive additives such as carbon black (CB) are indispensable components for manufacturing battery electrodes in addition to active materials. The concept of adhesive conductors employing fragmented carbon nanotube macrofilms (FCNTs) is demonstrated by constructing composite electrodes with a typical active material, LiMn2O4. The adhesive FCNT conductors provide not only a high electrical conductivity but also a strong adhesive force, functioning simultaneously as both the conductive additives and the binder materials for lithium-ion batteries. Such composite electrodes exhibit superior high-rate and retention capabilities compared to the electrodes using a conventional binder (PVDF) and a conductive additive (CB). An in situ tribology method combining wear track imaging and force measurement is employed to evaluate the adhesion strength of the adhesive FCNT conductors. The adhesive FCNT conductors exhibit higher adhesion strength than PVDF. It has further been confirmed that the adhesive FCNT conductor can be used in both cathodes and anodes and is proved to be a competent substitute for polymer binders to maintain mechanical integrity and at the same time to provide electrical connectivity of active materials in the composite electrodes. The organic-solvent-free electrode manufacturing offers a promising strategy for the battery industry.

  20. Strong light-field effects in correlated oraganic conductors

    Science.gov (United States)

    Iwai, Shinichiro; Kawakami, Yohei; Naitoh, Yota; Itoh, Hirotake; Ishihara, Sumio; Yonemitsu, Kenji

    Optical responses of organic conductors have attracted much attentions, because they exhibit ultrafast solid-state phase transitions in the conducting and/or dielectric natures upon photo-excitations. In this decade, photoinduced melting of correlated insulators with clear charge gap have been extensively investigated. On the other hand, optical rsponses of correlated metal has not been studied well. Here, we describe a charge localization induced by the 9.3 MV/cm instantaneous electric field of a 1.5 cycle (7 fs) infrared pulse in an organic conductor alpha- (bis[ethylenedithio]-tetrathiafulvelene)2I3. A large reflectivity change of 30 percent and a coherent charge oscillation along the time axis reflect the opening of the charge ordering gap in the metallic phase. This optical freezing of charges, which is the reverse of the photoinduced melting of electronic orders, is attributed to the 10 percent reduction of t driven by the strong, high-frequency electric field. Furthermore, the contribution of Coulomb repulsion will be discussed on the basis of the polarization dependence of the pump light and the theory.

  1. Printable elastic conductors with a high conductivity for electronic textile applications

    Science.gov (United States)

    Matsuhisa, Naoji; Kaltenbrunner, Martin; Yokota, Tomoyuki; Jinno, Hiroaki; Kuribara, Kazunori; Sekitani, Tsuyoshi; Someya, Takao

    2015-06-01

    The development of advanced flexible large-area electronics such as flexible displays and sensors will thrive on engineered functional ink formulations for printed electronics where the spontaneous arrangement of molecules aids the printing processes. Here we report a printable elastic conductor with a high initial conductivity of 738 S cm-1 and a record high conductivity of 182 S cm-1 when stretched to 215% strain. The elastic conductor ink is comprised of Ag flakes, a fluorine rubber and a fluorine surfactant. The fluorine surfactant constitutes a key component which directs the formation of surface-localized conductive networks in the printed elastic conductor, leading to a high conductivity and stretchability. We demonstrate the feasibility of our inks by fabricating a stretchable organic transistor active matrix on a rubbery stretchability-gradient substrate with unimpaired functionality when stretched to 110%, and a wearable electromyogram sensor printed onto a textile garment.

  2. 30 CFR 56.12048 - Communication conductors on power poles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Communication conductors on power poles. 56... Electricity § 56.12048 Communication conductors on power poles. Telegraph, telephone, or signal wires shall not be installed on the same crossarm with power conductors. When carried on poles...

  3. 30 CFR 75.513-1 - Electric conductor; size.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric conductor; size. 75.513-1 Section 75.513-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY... Electric conductor; size. An electric conductor is not of sufficient size to have adequate...

  4. 46 CFR 120.372 - Equipment and conductor grounding.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Equipment and conductor grounding. 120.372 Section 120... INSTALLATION Power Sources and Distribution Systems § 120.372 Equipment and conductor grounding. (a) All... together to a common ground by a normally non-current carrying conductor. Metallic cases of instruments...

  5. 21 CFR 868.1920 - Esophageal stethoscope with electrical conductors.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Esophageal stethoscope with electrical conductors... stethoscope with electrical conductors. (a) Identification. An esophageal stethoscope with electrical conductors is a device that is inserted into the esophagus to listen to a patient's heart and breath...

  6. 30 CFR 57.12048 - Communication conductors on power poles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Communication conductors on power poles. 57... MINES Electricity Surface and Underground § 57.12048 Communication conductors on power poles. Telegraph, telephone, or signal wires shall not be installed on the same crossarm with power conductors. When...

  7. 46 CFR 183.372 - Equipment and conductor grounding.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Equipment and conductor grounding. 183.372 Section 183... conductor grounding. (a) All metallic enclosures and frames of electrical equipment must be permanently... equipment must be bonded together to a common ground by a normally non-current carrying conductor....

  8. 30 CFR 77.503 - Electric conductors; capacity and insulation.

    Science.gov (United States)

    2010-07-01

    ... UNDERGROUND COAL MINES Electrical Equipment-General § 77.503 Electric conductors; capacity and insulation. Electric conductors shall be sufficient in size and have adequate current carrying capacity and be of such... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric conductors; capacity and...

  9. 30 CFR 75.513 - Electric conductor; capacity and insulation.

    Science.gov (United States)

    2010-07-01

    ... § 75.513 Electric conductor; capacity and insulation. All electric conductors shall be sufficient in size and have adequate current carrying capacity and be of such construction that a rise in temperature... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric conductor; capacity and insulation....

  10. High Temperature Protonic Conductors by Melt Growth

    Science.gov (United States)

    2006-11-21

    A.R. de Arellano-López, A. Sayir. “Microestructura y Comportamiento Plástico de Perovsquitas Conductoras Protónicas de Alta Temperatura ”. Bol. Soc...Conductores Protónicos de Alta Temperatura Crecidos por Fusión de Zona Flotante”. VII Reunión Nacional y VI Conferencia Iberoamericana (Electrocerámica

  11. High-temperature superconducting conductors and cables

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

    1996-09-01

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J{sub c} in high magnetic fields at temperatures near liq. N2`s bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J{sub c} at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices.

  12. The Conductor as a Transformational Leader.

    Science.gov (United States)

    Armstrong, Susan; Armstrong, Scott

    1996-01-01

    Identifies charisma and inspirational leadership as the most important characteristics of transformational leaders. Discusses how middle and secondary school music conductors can use the transformational leadership model. Summarizes key components of this model including positive modeling, sharing vision, and empowering others. Provides relevant…

  13. Crystal structure, stability, and optoelectronic properties of the organic-inorganic wide-band-gap perovskite CH3NH3BaI3 : Candidate for transparent conductor applications

    Science.gov (United States)

    Kumar, Akash; Balasubramaniam, K. R.; Kangsabanik, Jiban; Vikram, Alam, Aftab

    2016-11-01

    Structural stability, electronic structure, and optical properties of CH3NH3BaI3 hybrid perovskite are examined from theory as well as experiment. Solution-processed thin films of CH3NH3BaI3 exhibited a high transparency in the wavelength range of 400-825 nm (1.5-3.1 eV for which the photon current density is highest in the solar spectrum) which essentially justifies a high band gap of 4 eV obtained by theoretical estimation. Also, the x-ray diffraction patterns of the thin films match well with the {00 l } peaks of the simulated pattern obtained from the relaxed unit cell of CH3NH3BaI3 , crystallizing in the I 4 /m c m space group, with lattice parameters, a =9.30 Å, c =13.94 Å. Atom projected density of state and band structure calculations reveal the conduction and valence band edges to be comprised primarily of barium d orbitals and iodine p orbitals, respectively. The larger band gap of CH3NH3BaI3 compared to CH3NH3PbI3 can be attributed to the lower electronegativity coupled with the lack of d orbitals in the valence band of Ba2 +. A more detailed analysis reveals the excellent chemical and mechanical stability of CH3NH3BaI3 against humidity, unlike its lead halide counterpart, which degrades under such conditions. We propose La to be a suitable dopant to make this compound a promising candidate for transparent conductor applications, especially for all perovskite solar cells. This claim is supported by our calculated results on charge concentration, effective mass, and vacancy formation energies.

  14. Perovskite solar cells with CuI inorganic hole conductor

    Science.gov (United States)

    Takahashi, Kenta; Suzuki, Yoshikazu

    2017-08-01

    An organic material, 2,2‧,7,7‧-tetrakis(N,N-di-p-methoxyphenylamine)9,9‧-spirobifluorene (spiro-OMeTAD), is generally used as a hole conductor of perovskite solar cells (PSCs), but spiro-OMeTAD is much more expensive than other materials used in PSCs. In this study, we have prepared PSCs with a cost-effective CuI hole transport layer by spin coating. The merit of using spin coating for CuI is good compatibility with other steps, such as spin coating of a TiO2 electron transport layer and a perovskite active layer. The CuI-based PSC recorded power conversion efficiencies of η = 2.22% (max) on the day of production and η = 6.52% (max) after the 20 days of production. Moreover, the CuI-based PSC had a smaller hysteresis than the spiro-based PSC, suggesting that CuI is a highly promising alternative hole conductor for PSCs.

  15. EDITORIAL: Coated conductors and their applications Coated conductors and their applications

    Science.gov (United States)

    Freyhardt, Herbert C.; Lee, Dominic; Izumi, Teruo

    2010-01-01

    The attractive perspectives offered by coated conductors, known as the 2nd generation of high temperature superconductors (2G-HTS), have triggered broad and fruitful R&D efforts to make them ready for the marketplace. The anisotropic features of YBCO and its weak-link behavior require the processing of almost single crystalline thin films into flat tapes of coated conductors by basically two different methods: RABiTS—rolling-assisted biaxially textured substrates; and IBAD—ion-beam assisted deposition. Reliable processing technologies are now at hand, and critical current carrying capacities can be raised to almost 10-20% of the theoretically possible limit by optimizing current transfer through grain boundaries as well as flux pinning through control and design of the microstructural landscapes. The optimization of the in-field properties of the 2G-HTS wires, as well as the manufacturing of coated conductors with low ac losses and of assembled conductors for high current application remain active development areas. Cost reduction and more economic processing are still an issue. However, coated conductors are now beginning to penetrate the market, particularly for power and electrical applications, where savings in energy are essential and where the unique features of high temperature superconducting materials can be utilized. Major international conferences have followed up the progress in this exciting realm, and important workshops and discussion meetings have been held on this topic. Nonetheless, it was felt that a concise and up-to-date issue of Superconductor Science and Technology would be most welcome to summarize and collect the latest developments in processing and characterizing coated conductors, as well as drawing attention to the most innovative applications. The Guest Editors of this focus issue owe great thanks to those colleagues who were willing to contribute with their most recent findings to this issue on 'Coated conductors and their

  16. Superconducting homopolar motor and conductor development

    Science.gov (United States)

    Gubser, Donald U.

    1996-10-01

    The U.S. Navy has been developing superconducting homopolar motors for ship applications since 1969; a successful at-sea demonstration of the first motor, using NbTi wire for the magnet, was achieved in the early 1980s. Recently, this same motor was used as a test bed to demonstrate progress in high-critical-temperature superconducting magnet technology using bismuth-strontium- calcium-copper-oxide (BSCCO) compounds. In the fall of 1995, this motor achieved a performance of 124 kW operating at a temperature of 4.2 K and 91 kW while operating at 28 K. Future tests are scheduled using new magnets with conductors of both the 2223 and the 2212 BSCCO phases. This article describes the advantages of superconducting propulsion and recent progress in the development of BSCCO conductors for use in Navy power systems.

  17. Local noise in a diffusive conductor

    Science.gov (United States)

    Tikhonov, E. S.; Shovkun, D. V.; Ercolani, D.; Rossella, F.; Rocci, M.; Sorba, L.; Roddaro, S.; Khrapai, V. S.

    2016-07-01

    The control and measurement of local non-equilibrium configurations is of utmost importance in applications on energy harvesting, thermoelectrics and heat management in nano-electronics. This challenging task can be achieved with the help of various local probes, prominent examples including superconducting or quantum dot based tunnel junctions, classical and quantum resistors, and Raman thermography. Beyond time-averaged properties, valuable information can also be gained from spontaneous fluctuations of current (noise). From these perspective, however, a fundamental constraint is set by current conservation, which makes noise a characteristic of the whole conductor, rather than some part of it. Here we demonstrate how to remove this obstacle and pick up a local noise temperature of a current biased diffusive conductor with the help of a miniature noise probe. This approach is virtually noninvasive for the electronic energy distributions and extends primary local measurements towards strongly non-equilibrium regimes.

  18. Films of Carbon Nanomaterials for Transparent Conductors

    Directory of Open Access Journals (Sweden)

    Jun Wei

    2013-05-01

    Full Text Available The demand for transparent conductors is expected to grow rapidly as electronic devices, such as touch screens, displays, solid state lighting and photovoltaics become ubiquitous in our lives. Doped metal oxides, especially indium tin oxide, are the commonly used materials for transparent conductors. As there are some drawbacks to this class of materials, exploration of alternative materials has been conducted. There is an interest in films of carbon nanomaterials such as, carbon nanotubes and graphene as they exhibit outstanding properties. This article reviews the synthesis and assembly of these films and their post-treatment. These processes determine the film performance and understanding of this platform will be useful for future work to improve the film performance.

  19. Local noise in a diffusive conductor

    Science.gov (United States)

    Tikhonov, E. S.; Shovkun, D. V.; Ercolani, D.; Rossella, F.; Rocci, M.; Sorba, L.; Roddaro, S.; Khrapai, V. S.

    2016-01-01

    The control and measurement of local non-equilibrium configurations is of utmost importance in applications on energy harvesting, thermoelectrics and heat management in nano-electronics. This challenging task can be achieved with the help of various local probes, prominent examples including superconducting or quantum dot based tunnel junctions, classical and quantum resistors, and Raman thermography. Beyond time-averaged properties, valuable information can also be gained from spontaneous fluctuations of current (noise). From these perspective, however, a fundamental constraint is set by current conservation, which makes noise a characteristic of the whole conductor, rather than some part of it. Here we demonstrate how to remove this obstacle and pick up a local noise temperature of a current biased diffusive conductor with the help of a miniature noise probe. This approach is virtually noninvasive for the electronic energy distributions and extends primary local measurements towards strongly non-equilibrium regimes. PMID:27466216

  20. Local noise in a diffusive conductor.

    Science.gov (United States)

    Tikhonov, E S; Shovkun, D V; Ercolani, D; Rossella, F; Rocci, M; Sorba, L; Roddaro, S; Khrapai, V S

    2016-07-28

    The control and measurement of local non-equilibrium configurations is of utmost importance in applications on energy harvesting, thermoelectrics and heat management in nano-electronics. This challenging task can be achieved with the help of various local probes, prominent examples including superconducting or quantum dot based tunnel junctions, classical and quantum resistors, and Raman thermography. Beyond time-averaged properties, valuable information can also be gained from spontaneous fluctuations of current (noise). From these perspective, however, a fundamental constraint is set by current conservation, which makes noise a characteristic of the whole conductor, rather than some part of it. Here we demonstrate how to remove this obstacle and pick up a local noise temperature of a current biased diffusive conductor with the help of a miniature noise probe. This approach is virtually noninvasive for the electronic energy distributions and extends primary local measurements towards strongly non-equilibrium regimes.

  1. Ray class fields of conductor p

    CERN Document Server

    Stadnik, Maria

    2012-01-01

    We prove that (under the assumption of the generalized Riemann hypothesis) a totally real multiquadratic number field K has a positive density of primes p for which the ray class field of conductor p has an explicit description as the Hilbert class field H of K adjoin the real number \\zeta_p + \\zeta_p^{-1} if and only if K contains a unit of norm -1.

  2. A Review of Coated Conductor Development

    Institute of Scientific and Technical Information of China (English)

    徐永利; 时东陆

    2003-01-01

    The developments of coated conductor technology have been reviewed. It is shown that the critical current density of high-Tc wires can begreatly enhanced by using three-fold approaches: grain alignment, grain boundary doping, and optimization of the grain architecture. Major advances have been made in the last16 years mainly in three aspects: substrates, buffer layers and the YBCO layer. Cost is still the main concern for scale up, especially for the approach through vapor depositions, such as the PLD method. TFA-MOD or other CSD methods may be the trend to overcome cost and speed consideration during the scale up. However, high reliability and reproducibility will be the new focus for these techniques. Ni-alloy tapes seem to have advantages over pure Ni in terms of mechanicalstrength and oxidation resistance. Depositing a pure Ni layer on top of Ni-based alloys (such as Ni-Cr and Ni-W alloys) solves the problem of low strength ofNi and poor texture of Ni alloys. The RABiTS and IBAD are the two robust approaches for the texture generation. But the buffer materials and architectures being investigated remain unclear, though CeO2/YSZ/CeO2 and MgO are commonly used buffer layers for RABiTS and IBAD respectively. For the case where a buffer layer isunavoidable, a non-vacuum process would be suitable for low cost and scale up. However, none of the buffer layer fabrication processes through CSD has been demonstrated results good enough for long length coated conductor applications. While, a high Jc superconducting layer can be produced by TFA-MOD, which brings a bright future for coated conductors. Clearly, there are still many scientific and technological barriers to be overcome before any long length of high Jc coated conductor be produced commercially. But theoretical analyses and technological progress show the potential for the practical application of coatedconductor wires in the near future.

  3. AA, inner conductor of a magnetic horn

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    At the start-up of the AA and during its initial operation, magnetic horns focused the antiprotons emanating from the production target. These "current-sheet lenses" had a thin inner conductor (for minimum absorption of antiprotons), machined from aluminium to wall thicknesses of 0.7 or 1 mm. The half-sine pulses rose to 150 kA in 8 microsec. The angular acceptance was 50 mrad.

  4. Current-Induced Effects in Nanoscale Conductors

    OpenAIRE

    2005-01-01

    We present an overview of current-induced effects in nanoscale conductors with emphasis on their description at the atomic level. In particular, we discuss steady-state current fluctuations, current-induced forces, inelastic scattering and local heating. All of these properties are calculated in terms of single-particle wavefunctions computed using a scattering approach within the static density-functional theory of many-electron systems. Examples of current-induced effects in atomic and mole...

  5. Los conductores re-examinados: El transcurso del tiempo deteriora significativamente los conocimientos de los conductores

    Directory of Open Access Journals (Sweden)

    Francisco J. Martos

    2012-01-01

    Full Text Available Dos mil cinco conductores, 1204 hombres y 801 mujeres, una muestra representativa de la población española de conductores, fueron nuevamente examinados utilizando un cuestionario que reproducía fielmente un examen de conducir realizado por la Dirección General de Tráfico (DGT. Las preguntas fueron clasificadas en"“muy importantes", "importantes" y "poco importantes". El 96.5 % de los conductores, suspendió el examen. Los resultados eran tanto peores cuanto más tiempo había transcurridodesde la obtención del permiso de conducir. Esto era independiente de la importancia de las preguntas, de la mayor o menor frecuencia de conducción y afectaba por igual a hombres y mujeres. Las mujeres obtienen mejores puntuaciones en señalización mientras que los hombres son mejores en las preguntas de seguridad vial. Los resultados también demostraban que los conductores profesionales y los de mayor nivel educativo sufren un menor deterioro. Tales resultados nos llevan a considerar la relación que estos datos puedan tener en los niveles de accidentalidad y la conveniencia de establecer pautas para la actualización del conocimiento de los conductores. Finalmente, se discute la relevancia que el examen que se utiliza para obtener el permiso de conducir tiene como indicador o predictor de una futura conducción segura.

  6. Testing of the 3M Company Composite Conductor

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, John P [ORNL; Rizy, D Tom [ORNL; Kisner, Roger A [ORNL

    2010-10-01

    The 3M Company has developed a high-temperature low-sag conductor referred to as Aluminum-Conductor Composite-Reinforced or ACCR. The conductor uses an aluminum metal matrix material to replace the steel in conventional conductors. The objective of this work is to accelerate the commercial acceptance by electric utilities of this new conductor design by testing four representative conductor classes in controlled conditions. A unique facility called the Powerline Conductor Accelerated Testing (PCAT) Facility was built at ORNL for testing overhead conductors. The PCAT has been uniquely designed for testing overhead bare transmission line conductors at high currents and temperatures after they have been installed and tensioned to the manufacturer's specifications. The ability to operate a transmission line conductor in this manner does not exist elsewhere in the United States. Four classes of ACCR cable designed by the 3M Company have been successfully test at ORNL small, medium, large and small/compact. Based on these and other manufacturer tests, the 3M Company has successfully introduced the ACCR into the commercial market and has completed over twenty installations for utility companies.

  7. Isotropic magnetoresistance anomaly in the antiferromagnetic anisotropic conductor, β''(EDO-TTFVO)2FeCl4

    Science.gov (United States)

    Teramura, M.; Yasuzuka, S.; Yoshino, H.; Sasaki, T.; Fujiwara, H.; Sugimoto, T.; Hiraoka, T.; Hayashi, T.; Murata, K.

    2006-11-01

    We report the magnetoresistance (MR) in 2D-organic conductor, β''(EDOTTFVO)2FeCl4. We found an anomaly at 8T in MR, which is field-angle-independent. We speculate that this behavior is associated with from antiferromagnetic to paramagnetic transition, occurring at the same magnitude of magnetic field irrespective of field direction. To realize this situation, comparable magnitude of Jπd and Jdis required, which is rather rare the case. The isotropic nature in the magnetic transition is remarkable in the anisotropic organic conductors.

  8. Control of flux pinning in MOD YBCO coated conductor.

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.; Huang, Y.; Li, X.; Kodenkandath, T.; Rupich, M. W.; Schoop, U.; Verebelyi, D. T.; Thieme, C. L. H.; Siegal, E.; Holesinger, T. G.; Maiorov, B.; Civale, L.; Miller, D. J.; Maroni, V. A.; Li, J.; Martin, P. M.; Specht, E. D.; Goyal, A.; Paranthaman, M. P.; American Superconductor Corp.; LANL; ORNL

    2007-06-01

    NTwo different types of defect structures have been identified to be responsible for the enhanced pinning in metal organic deposited YBCO films. Rare earth additions result in the formation of nanodots in the YBCO matrix, which form uncorrelated pinning centers, increasing pinning in all magnetic field orientations. 124-type intergrowths, which form as laminar structures parallel to the ab-plane, are responsible for the large current enhancement when the magnetic field is oriented in the ab-plane. TEM studies showed that the intergrowths emanate from cuprous containing secondary phase particles, whose density is partially controlled by the rare earth doping level. Critical process parameters have been identified to control this phase formation, and therefore, control the f 24 intergrowth formation. This work has shown that through process control and proper conductor design, either by adjusting the composition or by multiple coatings of different functional layers, the desired angular dependence can be achieved.

  9. Diamagnetic phase transitions in two-dimensional conductors

    Energy Technology Data Exchange (ETDEWEB)

    Bakaleinikov, L.A., E-mail: bakal.ammp@mail.ioffe.ru [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Department of Mathematics and Physics, Faculty of Natural Sciences, University of Haifa, Campus Oranim, Tivon 36006 (Israel); Gordon, A. [Department of Mathematics and Physics, Faculty of Natural Sciences, University of Haifa, Campus Oranim, Tivon 36006 (Israel)

    2014-11-15

    A theory describing the susceptibility amplitude and the magnetic induction bifurcation near the dHvA driven diamagnetic phase transitions in quasi two-dimensional (2D) organic conductors of the (ET){sub 2}X with X=Cu(NCS){sub 2},KHg(SCN){sub 4},I{sub 3},AuBr{sub 2},IBr{sub 2}, etc. is presented. We show that there is a drastic increase in the temperature and magnetic field dependence of the susceptibility amplitude on approaching the diamagnetic phase transition point. Near the phase transition point the temperature and magnetic field dependences are fitted by the ones typical of the mean-field phase transition theory. These dependences confirm the long-range character of the magnetic interactions among the conduction electrons leading to diamagnetic phase transitions. We demonstrate that the magnetic induction splitting of nuclear magnetic resonance (NMR) and muon spin-rotation spectroscopy (μSR) lines due to two Condon domains decreases tending to zero on approaching the diamagnetic phase transition. This decrease is fitted by the temperature and magnetic field dependence of the susceptibility characteristic of the mean-field theory of phase transitions. Performing new susceptibility, NMR and μSR experiments will enable to detect diamagnetic phase transitions and Condon domains in quasi 2D metals. - Highlights: • A theory of diamagnetic phase transitions (DPTs) is presented in 2D organic conductors. • The behaviour of the susceptibility amplitude and the induction splitting is shown near the DPT. • The calculated quantities are described by the mean-field theory of phase transitions.

  10. 46 CFR 111.05-33 - Equipment safety grounding (bonding) conductors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Equipment safety grounding (bonding) conductors. 111.05... § 111.05-33 Equipment safety grounding (bonding) conductors. (a) Each equipment-grounding conductor must... 110.10-1). (b) Each equipment-grounding conductor (other than a system-grounding conductor) of a...

  11. Transport AC Losses in Striated YBCO Coated Conductors (Postprint)

    Science.gov (United States)

    2012-02-01

    AFRL-RZ-WP-TP-2012-0124 TRANSPORT AC LOSSES IN STRIATED YBCO COATED CONDUCTORS (POSTPRINT) G.A. Levin and P.N. Barnes Mechanical Energy...TRANSPORT AC LOSSES IN STRIATED YBCO COATED CONDUCTORS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...2006. 14. ABSTRACT DC current-voltage characteristics and transport ac losses of striated and non-striated Y1Ba2Cu3O7-δ ( YBCO ) coated conductors

  12. Magnetically Guiding Atoms with Current-Carrying Conductors

    Institute of Scientific and Technical Information of China (English)

    刘南春; 高伟建; 印建平

    2002-01-01

    We propose a novel magnetic guide for cold neutral atoms using some current-carrying conductors. The spatial distributions of the magnetic fields from a V-shaped or U-shaped current-carrying conductor are calculated, and the relationship between the resulting magnetic field and the parameters of the current-carrying conductors is analysed in detail. The result shows that these current-carrying conductors can be used to realize a single or a controllable double magnetic guide of cold atoms in the weak-field-seeking state, and to construct various atom-optical elements, and even to realize a single-mode atomic waveguiding under certain conditions.

  13. First qualification of ITER Toroidal Field Coil conductor jacketing

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Kazuya, E-mail: hamada.kazuya@jaea.go.jp [Japan Atomic Energy Agency (Japan); Takahashi, Yoshikazu; Isono, Takaaki; Nunoya, Yoshihiko; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Tsutsumi, Fumiaki; Koizumi, Norikiyo; Nakajima, Hideo; Okuno, Kiyoshi [Japan Atomic Energy Agency (Japan); Matsuda, Hidemitsu; Yano, Yoshitaka [Nippon Steel Engineering Co. Ltd (Japan); Devred, Arnauld; Bessette, Denis [ITER Organization (France)

    2011-10-15

    The Japan Atomic Energy Agency (JAEA) has the responsibility to procure 25% of the ITER Toroidal Field Coil conductors as the Japanese Domestic Agency (JADA) in the ITER project. The TF conductor is a circular shaped, cable-in-conduit conductor, composed of a cable and a stainless steel conduit (jacket). The outer diameter and maximum length of the TF conductor are 43.7 mm and 760 m, respectively. JAEA started to produce strand, cables and jacket sections and to construct a conductor manufacturing (jacketing) facility in 2008. Following preparation in December 2009 of the jacketing facility, the dummy cable, the jacket sections and fabrication procedures, such as welding, cable insertion, compaction and spooling, JAEA manufactured a 760 m long Cu dummy conductor for process qualification. Into the 760 m long Cu dummy conductor jacketing, JAEA successfully inserted the cable with a maximum force of 32 kN. The outer diameter of the cross section of the spooled conductor was 43.7 {+-} 0.15 mm, which complies with the ITER target requirement of 43.7 {+-} 0.3 mm. Following qualification of all manufacturing processes, JAEA has started to fabricate superconducting conductors for the TF coils.

  14. The Famous Conductor,VuZhu Dokyi

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    VUzhu Dokyi,now the head of the Tibetan Song and Dance Ensemble is a second-grade conductor of the state,a member of Chinese Musicians’Association,the vice-president of Tibetan Musicians’Association and a council member of the Chinese Chorus Artists’Association.In 1960 he was admitted to the Tianjin Conservatory of Music and followed Qiu Jianhua,the famous music educator,to learn violin.After graduation,he was first violin in the Tibetan Song and Dance Ensemble Orchestra.

  15. Precision gold conductors for HMCs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Widmer, M.R.

    1994-08-01

    Ti/Pd/Au multiple code coded switch (MCCS) networks were built and compared to Cr/Au MCCS networks. The data showed no measurable difference between the two systems. Interface resistance of both types of networks was measured as a diagnostic aid to determine if hydrogen was affecting the Ti/Pd/Au MCCS networks. The data showed that although hydrogen does affect Ti/Pd/Au, the changes are not significant with respect to MCCS environments. An evaluation of several proprietary gold electroplating solutions for use in the production of Ti/Pd/Au conductors was performed. All the testing results were comparable to the current product requirements.

  16. AA, Inner Conductor of Magnetic Horn

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    Antiprotons emerging at large angles from the production target (hit by an intense 26 GeV proton beam from the PS), were focused into the acceptance of the injection line of the AA by means of a "magnetic horn" (current-sheet lens). Here we see an early protype of the horn's inner conductor, machined from solid aluminium to a thickness of less than 1 mm. The 1st version had to withstand pulses of 150 kA, 15 us long, every 2.4 s. See 8801040 for a later version.

  17. Superconductivity and magnetic field induced spin density waves in the (TMTTF)2X family

    Science.gov (United States)

    Balicas, L.; Behnia, K.; Kang, W.; Canadell, E.; Auban-Senzier, P.; Jérome, D.; Ribault, M.; Fabre, J. M.

    1994-10-01

    We report magnetotransport measurements in the quasi one dimensional (Q-1-D) organic conductor (TMTTF)2Br at pressures up to 26 kbar, clown to 0.45 K in magnetic fields up to 19 T along the c^{ast} direction. It is found that a superconducting ground state is stabilized under 26 kbar at T_C = 0.8 K. No magnetic field induced spin density wave (FISDW) transitions are observed below 19T unlike other Q-1-D superconductors pertaining to the selenium series. The computed amplitude of the interchain coupling along transverse directions is unable to explain the missing; FISDW instability.

  18. Imperfect nesting and transport properties in unconventional density waves

    Science.gov (United States)

    Dóra, Balázs; Maki, Kazumi; Virosztek, Attila

    2002-10-01

    We consider the effect of imperfect nesting in quasi-one-dimensional unconventional density waves (DW's). The phase diagram is very close to those in a conventional DW's. The linear and non-linear aspects of the electric conductivity are discussed. At T=0 the frequency dependent electric conductivity develops a small dip at low frequencies. The threshold electric field depends strongly on the imperfect nesting parameter, allowing us to describe very well the measured threshold electric field in the low temperature phase of the quasi-two-dimensional organic conductor, α-(BEDT-TTF)2KHg(SCN)4.

  19. Note: Adhesive stamp electrodes using spider silk masks for electronic transport measurements of supra-micron sized samples

    Science.gov (United States)

    Steven, E.; Jobiliong, E.; Eugenio, P. M.; Brooks, J. S.

    2012-04-01

    A procedure for fabricating adhesive stamp electrodes based on gold coated adhesive tape used to measure electronic transport properties of supra-micron samples in the lateral range 10-100 μm and thickness >1 μm is described. The electrodes can be patterned with a ˜4 μm separation by metal deposition through a mask using Nephila clavipes spider dragline silk fibers. Ohmic contact is made by adhesive lamination of a sample onto the patterned electrodes. The performance of the electrodes with temperature and magnetic field is demonstrated for the quasi-one-dimensional organic conductor (TMTSF)2PF6 and single crystal graphite, respectively.

  20. 30 CFR 56.12010 - Isolation or insulation of communication conductors.

    Science.gov (United States)

    2010-07-01

    ... conductors. 56.12010 Section 56.12010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... MINES Electricity § 56.12010 Isolation or insulation of communication conductors. Telephone and low... energized power conductors or any other power source....

  1. Transport properties and giant Shubnikov-de Haas oscillations in the first organic conductor with metal complex anion containing selenocyanate ligand, (ET){sub 2}TlHg(SeCN){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Laukhin, V.N. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France)]|[Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, Chernogolovka, MD 142432 (Russian Federation); Audouard, A. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France); Rakoto, H. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France); Broto, J.M. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France); Goze, F. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France); Coffe, G. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France); Brossard, L. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France); Redoules, J.P. [Service National des Champs Magnetiques Pulses du CNRS et Laboratoire de Physique des Solides, URA CNRS 074, Complexe Scientifique de Rangueil, 31077 Toulouse (France); Kartsovnik, M.V. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, MD 142432 (Russian Federation); Kushch, N.D. [Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, Chernogolovka, MD 142432 (Russian Federation); Buravov, L.I.

    1995-05-01

    Temperature dependence of the resistivity in various crystallographic directions and high pulsed field magnetoresistance of organic metal {alpha}-(ET){sub 2}TlHg(SeCN){sub 4} have been studied at temperatures down to 80 mK. Giant Shubnikov-de Haas oscillations, which are attributed to the two-dimensional nature of the cylindrical Fermi surface with a very small warping along the direction of the lowest conductivity have been observed. Four harmonics of the fast oscillations with fundamental frequency F{sub 0}=653{+-}3 T and slow frequency oscillations with F{sub s}=38{+-}5 T have been revealed. (orig.).

  2. Shubnikov-de Haas Oscillations in New Organic Conductors (ET)8[ Hg4Cl12(C6H5Cl)2] and (ET)8[ Hg4Cl12(C6H5Br)2

    OpenAIRE

    Lyubovskii, R.; Pesotskii, S.; Gilevski, A.; Lyubovskaya, R.

    1996-01-01

    The results of the investigations of Shubnikov-de Haas oscillations in the quasi-two-dimensional organic complexes (ET)8[ Hg4Cl12(C6H5Cl)2] , where X = CI, Br in the magnetic fields up to 40 T were reported. These results allow one to obtain some information about Fermi surface in the mentioned complexes. Shubnikov-de Haas oscillations in the compound with X = Cl correspond at least to two different cylindrical sheets of Fermi surface with the cross-section in (bc)-plane of 13% and 20% Brillo...

  3. Testing of the 3M Company ACCR Conductor

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, J.P.; RIzy, D.T.; Kisner, R.A.; Deve, H.E. (3M Comp.)

    2010-09-15

    The 3M Company has developed a high-temperature low-sag conductor referred to as Aluminum- Conductor Composite-Reinforced or ACCR. The conductor uses an aluminum metal matrix material to replace the steel in conventional conductors so the core has a lower density and higher conductivity. The objective of this work is to accelerate the commercial acceptance by electric utilities of these new conductor designs by testing four representative conductor classes in controlled conditions. Overhead transmission lines use bare aluminum conductor strands wrapped around a steel core strands to transmit electricity. The typical cable is referred to as aluminum-conductor steel-reinforced (ACSR). The outer strands are aluminum, chosen for its conductivity, low weight, and low cost. The center strand is of steel for the strength required to support the weight without stretching the aluminum due to its ductility. The power density of a transmission corridor has been directly increased by increasing the voltage level. Transmission voltages have increased from 115-kV to 765- kV over the past 80 years. In the United States, further increasing the voltage level is not feasible at this point in time, so in order to further increase the power density of a transmission corridor, conductor designs that increase the current carrying capability have been examined. One of the key limiting factors in the design of a transmission line is the conductor sag which determines the clearance of the conductor above ground or underlying structures needed for electrical safety. Increasing the current carrying capability of a conductor increases the joule heating in the conductor which increases the conductor sag. A conductor designed for high-temperature and lowsag operation requires an engineered modification of the conductor materials. To make an advanced cable, the 3M Company solution has been the development of a composite conductor consisting of Nextel ceramic fibers to replace the steel core and

  4. Maximum permissible voltage of YBCO coated conductors

    Science.gov (United States)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.

    2014-06-01

    Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  5. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  6. Novel processing of HTS based conductors

    Science.gov (United States)

    Ginley, D. S.; Venturini, E. L.; Kwak, J. F.; Baughman, R. J.; Bourcier, R. J.; Mitchell, M. A.; Morosin, B.; Halloran, J. W.; Neal, N. J.; Capone, D. W.

    1990-04-01

    Conductor development is one of the major long term goals in high temperature superconductor research. Two promising processing technologies that were utilized to produce superconducting HTS conductors are reported. First, melt spun YBa2Cu3O7 fibers rapid thermal processed for 1 to 8 sec at 950 to 1075 C have (Tc)'s to 92 K, J(sub c)'s to 1100 A/sq cm and the orthorhombic twinned morphology typical for high quality YBa2Cu3O7. A processing matrix of time, temperature and composition for these fibers shows that slightly CuO-rich starting compositions give the best results. Second, silver tube encapsulated wires of Bi(1.7)Pb(0.3)Sr2Ca2Cu3O10 were made by extrusion, wire drawing and cold rolling. The resulting tapes show orientation of the crystallites, zero resistance up to 100 K and improved magnetic hysteresis above 50 K. The combination of mechanical reprocessing and extended thermal anneals near 850 C appears to significantly improve these materials.

  7. The Identification of Conductor-Distinguished Functions of Conducting

    Science.gov (United States)

    Gumm, Alan J.; Battersby, Sharyn L.; Simon, Kathryn L.; Shankles, Andrew E.

    2011-01-01

    The purpose of the present study was to identify whether conductors distinguish functions of conducting similarly to functions implied in previous research. A sample of 84 conductors with a full range of experience levels (M = 9.8) and of a full range of large ensemble types and ensemble age levels rated how much they pay attention to 82…

  8. Elastically stretchable thin film conductors on an elastomeric substrate

    Science.gov (United States)

    Jones Harris, Joyelle Elizabeth

    Imagine a large, flat screen television that can be rolled into a small cylinder after purchase in the store and then unrolled and mounted onto the wall of a home. The electronic devices within the television must be able to withstand large deformation and tensile strain. Consider a robot that is covered with an electronic skin that simulates human skin. The skin would enable the machine to lift an elderly person with care and sensitivity. The skin will endure repeated deformation with the highest tensile strains being experienced at the robot's joints. These applications and many others will benefit from stretchable electronic circuitry. While several different methods have been employed to create stretchable electronics, all methods use a common tool -- stretchable conductors. Therefore, the goal of this thesis work was to fabricate elastically stretchable conductors that can be used in stretchable electronics. We deposited Au thin films on an elastomeric substrate, and the resulting conductors remained electrically continuous when stretched by 30% and more. We developed photolithographic processes that can be used to pattern elastically stretchable conductors with a 10 mum resolution. We fabricated bi-level stretchable conductors that are separated by an elastomeric insulator and are electrically connected through via holes in the insulator. We applied our bi-level conductors to create a stretchable resistor-inductor-capacitor (RLC) circuit with a tunable resonant frequency. We also used stretchable conductors to measure action potentials in biological samples. This thesis describes the fabrication and application of our elastically stretchable conductors.

  9. Beyond the Beat: Modelling Intentions in a Virtual Conductor

    NARCIS (Netherlands)

    Maat, ter Mark; Ebbers, Rob M.; Reidsma, Dennis; Nijholt, Anton

    2008-01-01

    We describe our research on designing and implementing a Virtual Conductor. That is, a virtual human (embodied agent) that acts like a human conductor in its interaction with a real, human orchestra. We reported previously on a first version that used a digital musical score to lead an orchestra. Th

  10. Overcurrent experiments on HTS tape and cable conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Jensen, Kim Høj; Træholt, Chresten;

    2001-01-01

    their critical current. In this light, it is important to investigate the response of HTS tapes and cable conductors to overcurrents several times the critical current. A number of experiments have been performed on HTS tapes and cable conductors, with currents up to 20 times the critical current. During...... overcurrent experiments, the voltage, and the temperature were measured as functions of time in order to investigate the dynamic behavior of the HTS tape and cable conductor. After each experiment, damage to the superconductors was assessed by measuring the critical current. Preliminary results show...... that within seconds an HTS tape (critical current=17 A) heats above room temperature with an overcurrent larger than 140 A. Similar overcurrent experiments showed that a HTS cable conductor could sustain damage with overcurrents exceeding 10 times the critical current of the cable conductor....

  11. ELECTRODYNAMIC STABILITY COMPUTATIONS FOR FLEXIBLE CONDUCTORS OF THE AERIAL LINES

    Directory of Open Access Journals (Sweden)

    I. I. Sergey

    2015-01-01

    Full Text Available In aerial transmission lines aluminium multiwire conductors are in use. Owing to their flexible design the electrodynamic effect of short circuit currents may lead to intolerable mutual rendezvous and even cross-whipping of the phase conductors. The increasing motion of the conductors caused by effect of the short-circuit electrodynamic force impulse is accompanied by the dynamic load impact affecting the conductors, insulating and supporting constructions of the aerial lines. Intensity of the short-circuit currents electrodynamic impact on the flexible conductors depends on the short circuit current magnitude. For research into electrodynamic endurance of the conductors of the aerial lines located at the vertices of arbitrary triangle with spans of a large length, the authors assume the conductor analytical model in the form of a flexible tensile thread whose mass is distributed evenly lengthwise the conductor. With this analytical model, by the action of the imposed forces the conductor assumes the form conditioned by the diagram of applied external forces, and resists neither bending nor torsion. The initial conditions calculation task reduces to solving the flexible thread statics equations. The law of motion of the conductor marginal points comes out of the conjoint solution of dynamic equations of the conductor and structural components of the areal electric power lines. Based on the proposed algorithm, the researchers of the Chair of the Electric Power Stations of BNTU developed a software program LINEDYS+, which in its characteristics yields to no foreign analogs, e. g. SAMSEF. To calculate the initial conditions they modified a software program computing the flexible conductor mechanics named MR 21. The conductor short-circuit electrodynamic interaction estimation considers structural elements of the areal lines, ice and wind loads, objective parameters of the short circuit. The software programs are accommodated with the simple and

  12. Synthesis and Characterization of Ethylenedithio-MPTTF-PTM Radical Dyad as a Potential Neutral Radical Conductor

    DEFF Research Database (Denmark)

    Souto, Manuel; Bendixen, Dan; Jensen, Morten

    2016-01-01

    ) unit by a π-conjugated bridge (1) that behaves as a semiconductor under high pressure. With the aim of developing a new material with improved conducting properties, we have designed and synthesized the radical dyad 2 which was functionalized with an ethylenedithio (EDT) group in order to improve......During the last years there has been a high interest in the development of new purely-organic single-component conductors. Very recently, we have reported a new neutral radical conductor based on the perchlorotriphenylmethyl (PTM) radical moiety linked to a monopyrrolo-tetrathiafulvalene (MPTTF...... the intermolecular interactions of the tetrathiafulvalene (TTF) subunits. The physical properties of the new radical dyad 2 were studied in detail in solution to further analyze its electronic structure....

  13. Plasma Waves and Jets from Moving Conductors

    CERN Document Server

    Gralla, Samuel E

    2016-01-01

    We consider force-free plasma waves launched by the motion of conducting material through a magnetic field. We develop a spacetime-covariant formalism for perturbations of a uniform magnetic field and show how the transverse motion of a conducting fluid acts as a source. We show that fast-mode waves are sourced by the compressibility of the fluid, with incompressible fluids launching a pure-Alfven outflow. Remarkably, this outflow can be written down in closed form, at the nonlinear level, for an arbitrary incompressible flow. The instantaneous flow velocity is imprinted on the magnetic field and transmitted away at the speed of light, carrying detailed information about the conducting source at the time of emission. These results can be applied to transients in pulsar outflows and to jets from neutron stars orbiting in the magnetosphere of another compact object. We discuss jets from moving conductors in some detail.

  14. Microwave Loss Reduction in Cryogenically Cooled Conductors

    CERN Document Server

    Finger, R

    2015-01-01

    Measurements of microwave attenuation at room temperature and 4.2 K have been performed on some conductors commonly used in receiver input circuits. The reduction in loss on cooling is substantial, particularly for copper and plated gold, both of which showed a factor of 3 loss reduction. Copper passivated with benzotriazole shows the same loss as without passivation. The residual resistivity ratio between room temperature and 4.2 K, deduced from the measurements using the classical skin effect formula, was smaller than the measured DC value to a degree consistent with conduction in the extreme anomalous skin effect regime at cryogenic temperatures. The measurements were made in the 5-10 GHz range. The materials tested were: aluminum alloys 1100-T6 and 6061-O, C101 copper, benzotriazole treated C101 copper, and brass plated with electroformed copper, Pur-A-Gold 125-Au soft gold, and BDT200 bright gold.

  15. Alternative fiber optic conductor for laboratory practices

    Science.gov (United States)

    Calderon Ocampo, Juan F.; Jaramillo Florez, Samuel A.; Amaya Rodriguez, Juan C.

    1995-10-01

    Due to the high cost and difficulty in obtaining an optical fiber sample to be used in laboratory tests, we have given ourselves the task of looking for an adequate optical-fiber alternative for laboratory practices. We have as a result, found an object that can be used as an alternate optical conductor. This object called 'Venoclisis Hose', is a cylindrical plastic tube, hollow inside, whose main use has been in medical applications as a conveyor of liquids going in or coming out of the human body. In this document, the tests carried out and the results obtained to characterize the venoclisis as an optical fiber are described. This project was undertaken in order to propose the use of Venoclisis as an alternate optical fiber for laboratory work, due primarily to its low costs, as well as how easy it to acquire and measure its parameters as an optical fiber.

  16. Conductors and Newforms for (1,1)

    Indian Academy of Sciences (India)

    Joshua Lansky; A Raghuram

    2004-11-01

    Let be a non-Archimedean local field whose residue characteristic is odd. In this paper we develop a theory of newforms for (1,1)(), building on previous work on $SL_2(F)$. This theory is analogous to the results of Casselman for $GL_2(F)$ and Jacquet, Piatetski-Shapiro, and Shalika for $GL_n(F)$. To a representation π of (1,1)(), we attach an integer () called the conductor of , which depends only on the -packet containing . A newform is a vector in which is essentially fixed by a congruence subgroup of level ()$. We show that our newforms are always test vectors for some standard Whittaker functionals, and, in doing so, we give various explicit formulae for newforms.

  17. Random matrix model for disordered conductors

    Indian Academy of Sciences (India)

    Zafar Ahmed; Sudhir R Jain

    2000-03-01

    We present a random matrix ensemble where real, positive semi-definite matrix elements, , are log-normal distributed, $\\exp[-\\log^{2}(x)]$. We show that the level density varies with energy, , as 2/(1 + ) for large , in the unitary family, consistent with the expectation for disordered conductors. The two-level correlation function is studied for the unitary family and found to be largely of the universal form despite the fact that the level density has a non-compact support. The results are based on the method of orthogonal polynomials (the Stieltjes-Wigert polynomials here). An interesting random walk problem associated with the joint probability distribution of the ensuing ensemble is discussed and its connection with level dynamics is brought out. It is further proved that Dyson's Coulomb gas analogy breaks down whenever the confining potential is given by a transcendental function for which there exist orthogonal polynomials.

  18. Frequency Dependent Losses in Transmission Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdóttir, Unnur Stella

    2011-01-01

    Denmark is taking on the exciting project of undergrounding the electricity transmission grid. In 2009 it was decided by the Danish government to underground large parts of the 400 kV and the entire 132-150 kV transmission network before the end of 2030. For ensuring network stability...... and economical gain, such severe network changes necessitate correct estimation and optimisation of load conditions in the cable grid. Both IEC and IEEE have published standards for rating transmission cables' current carrying capacity. These standards are based on assumptions of a number of parameters...... of better calculation of the AC resistance of transmission cable conductors, in particular regarding higher frequencies. In this way, also losses under harmonics can be covered. Furthermore, the model is suitable for modelling of transient attenuation in high voltage cables. The AC resistance is calculated...

  19. HTS current lead units prepared by the TFA-MOD processed YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Shiohara, K.; Sakai, S.; Ishii, Y. [Tokai University, 1117 Kita-Kaname, Hiratsuka, Kanagawa 259-1292 (Japan); Yamada, Y., E-mail: yyamaday@keyaki.cc.u-tokai.ac.j [Tokai University, 1117 Kita-Kaname, Hiratsuka, Kanagawa 259-1292 (Japan); Tachikawa, K. [Tokai University, 1117 Kita-Kaname, Hiratsuka, Kanagawa 259-1292 (Japan); Koizumi, T.; Aoki, Y.; Hasegawa, T. [SWCC Showa Cable System Co., LTD, 4-1-1 Minami-Hashimoto, Sagamihara, Kanagawa 229-1133 (Japan); Tamura, H.; Mito, T. [NIFS National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)

    2010-11-01

    Two superconducting current lead units have been prepared using ten coated conductors of the Tri-Fluoro-Acetate - Metal Organic Deposition (TFA-MOD) processed Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}}(YBCO) coated conductors with critical current (I{sub c}) of about 170 A at 77 K in self-field. The coated conductors are 5 mm in width, 190 mm in length and about 120 {mu}m in overall thickness. The 1.5 {mu}m thick superconducting YBCO layer was synthesized through the TFA-MOD process on Hastelloy{sup TM} C-276 substrate tape with two buffer oxide layers of Gd{sub 2}Zr{sub 2}O{sub 7} and CeO{sub 2}. The five YBCO coated conductors are attached on a 1 mm thick Glass Fiber Reinforced Plastics (GFRP) board and soldered to Cu caps at the both ends. We prepared two 500 A-class current lead units. The DC transport current of 800 A was stably applied at 77 K without any voltage generation in all coated conductors. The voltage between both Cu caps linearly increased with increasing the applied current, and was about 350 {mu}V at 500 A in both current lead units. According to the estimated values of the heat leakage from 77 K to 4.2 K, the heat leakage for the current lead unit was 46.5 mW. We successfully attained reduction of the heat leakage because of improvement of the transport current performance (I{sub c}), a thinner Ag layer of YBCO coated conductor and usage of the GFRP board for reinforcement instead of a stainless steel board used in the previous study. The DC transport current of 1400 A was stably applied when the two current lead units were joined in parallel. The sum of the heat leakages from 77 K to 4.2 K for the combined the current lead units was 93 mW. In comparison with the conventional Cu current leads by gas-cooling, it could be noted that the heat leakage of the current lead is about one order of magnitude smaller than that of the Cu current lead.

  20. Modelling the transient emission from a twin conductor cable

    OpenAIRE

    2016-01-01

    Using the equations of transmission line theory, a programme is developed to simulate the response of an open-circuit line to a step pulse. This is compared with the observed response of a twin-conductor cable. It is deduced that not all of the current delivered to the send conductor arrives back via the return conductor. Some of it departs in the form of radiated emission. A virtual capacitor is used to simulate this, with limited success. However, by adding a second virtual capacitor to sim...

  1. 33 CFR 183.430 - Conductors in circuits of less than 50 volts.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Conductors in circuits of less... Requirements § 183.430 Conductors in circuits of less than 50 volts. (a) Each conductor in a circuit that has a...; resistance conductors that control circuit amperage; and pigtails of less than seven inches of exposed length....

  2. 33 CFR 183.435 - Conductors in circuits of 50 volts or more.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Conductors in circuits of 50... Requirements § 183.435 Conductors in circuits of 50 volts or more. (a) Each conductor in a circuit that has a nominal voltage of 50 volts or more must be: (1) A conductor that has insulation listed and...

  3. 30 CFR 56.12005 - Protection of power conductors from mobile equipment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of power conductors from mobile... MINES Electricity § 56.12005 Protection of power conductors from mobile equipment. Mobile equipment shall not run over power conductors, nor shall loads be dragged over power conductors, unless...

  4. The use of experimental data in constraining the tight-binding band parameters of quasi-two-dimensional organic molecular metals: application to α-(BEDT- TTF)2KHg(SCN)4

    Science.gov (United States)

    Harrison, N.; Rzepniewski, E.; Singleton, J.; Gee, P. J.; Honold, M. M.; Day, P.; Kurmoo, M.

    1999-09-01

    Whilst tight-binding bandstructure calculations are very successful in describing the Fermi-surface configuration in many quasi-two-dimensional organic molecular metals, the detailed topology of the predicted Fermi surface often differs from that measured in experiments. This is very significant when, for example, the formation of a density-wave state depends critically on details of the nesting of Fermi-surface sheets. These differences between theory and experiment probably result from the limited accuracy to which the icons/Journals/Common/pi" ALT="pi" ALIGN="TOP"/>-orbitals of the component molecules (which give rise to the transfer integrals of the tight-binding bandstructure) are known. In order to surmount this problem, we have derived a method whereby the transfer integrals within a tight-binding bandstructure model are adjusted until the detailed Fermi-surface topology is in good agreement with a wide variety of experimental data. The method is applied to the charge-transfer salt icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/>-(BEDT-TTF)2KHg(SCN)4, the Fermi surface of which has been the source of much speculation in recent years. The Fermi surface obtained differs in detail from previous bandstructure calculation findings. In particular, the quasi-one-dimensional component of the Fermi surface is more strongly warped. This implies that upon nesting of these sheets, significant parts of the quasi-one-dimensional sheets remain, leading to a complicated Fermi-surface topology within the low-temperature, low-magnetic-field phase. In contrast to previous models of this phase, the model for the reconstructed Fermi surface in this work can explain virtually all of the current experimental observations in a consistent manner.

  5. Organic Semiconductors and Conductors with tert-Butyl Substituents

    Directory of Open Access Journals (Sweden)

    Toshiki Higashino

    2012-08-01

    Full Text Available Tetrathiafulvalene (TTF, pentacene, and quarterthiophene with tert-butyl substituents are synthesized, and the crystal structures and the transistor properties are investigated. The tetracyanoquinodimethane (TCNQ complex of tert-butyl TTF constructs highly one-dimensional segregated columns with tetragonal crystal symmetry.

  6. Mixed density wave state in quasi-2D organic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Katono, K., E-mail: k_katono@eng.hokudai.ac.jp [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Ichimura, K. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo 060-8628 (Japan); Kawashima, Y.; Yamaya, K. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Tanda, S. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo 060-8628 (Japan)

    2012-06-01

    The density wave phase of {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} was investigated by transport properties and magnetic susceptibility. The density wave transition was observed as a broad increase at T{sub DW}=9 K by resistance measurement. Temperature dependence of the static magnetic susceptibility {chi} shows a large Curie tail below 100 K. By subtracting the Curie component, we found that the magnetic susceptibility increases like weak ferromagnetism with decreasing temperature below 7.4 K. The gradual increase of {chi} below T{sub DW} is not expected in simple CDW or SDW, where the magnetic susceptibility decreases with decreasing temperature due to the reduction of Pauli paramagnetic component. To explain the weak ferromagnetic behavior, we consider the coexistence of CDW and SDW. We propose a model of the mixed density wave, where CDW exists with antiferromagnetically coupled canting spins.

  7. Charge ordering in low dimensional organic conductors: Structural aspects

    Energy Technology Data Exchange (ETDEWEB)

    Pouget, Jean-Paul; Foury-Leylekian, Pascale [Laboratoire de Physique des Solides, Universite Paris-sud, CNRS UMR 8502, Batiment 510, 91405 Orsay Cedex (France); Alemany, Pere [Departament de Quimica Fisica and Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona, Diagonal 627, 08028 Barcelona (Spain); Canadell, Enric [Institut de Ciencia de Materials de Barcelona, CSIC, Campus UAB, 08193 Bellaterra (Spain)

    2012-05-15

    The paper points out the importance of the coupling between anions and donors in order to achieve the 4k{sub F} charge localization observed in (TMTTF){sub 2}PF{sub 6}, {delta}-(EDT-TTF-CONMe{sub 2}){sub 2}Br and (o-DMTTF){sub 2}Cl/Br salts, the 2k{sub F} charge density wave (CDW) ground state of {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} and the metal to insulator transition of {alpha}-(BEDT-TTF){sub 2}I{sub 3}. This coupling leads to a cooperative displacement wave of the anions accompanied by a modulation of the density of {pi} holes on the donors. We distinguish two principal anion-donor coupling mechanisms: a direct mechanism via the Hartree anion potential on donor sites and an indirect mechanism via the polarization of {sigma} bonds activated by the modification of the H bonds network. Both kinds of interaction are tuned by the relative displacement of the anions with respect to the donors. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Mixed density wave state in quasi-2D organic conductor

    Science.gov (United States)

    Katono, K.; Ichimura, K.; Kawashima, Y.; Yamaya, K.; Tanda, S.

    2012-06-01

    The density wave phase of α-(BEDT-TTF)2KHg(SCN)4 was investigated by transport properties and magnetic susceptibility. The density wave transition was observed as a broad increase at TDW=9 K by resistance measurement. Temperature dependence of the static magnetic susceptibility χ shows a large Curie tail below 100 K. By subtracting the Curie component, we found that the magnetic susceptibility increases like weak ferromagnetism with decreasing temperature below 7.4 K. The gradual increase of χ below TDW is not expected in simple CDW or SDW, where the magnetic susceptibility decreases with decreasing temperature due to the reduction of Pauli paramagnetic component. To explain the weak ferromagnetic behavior, we consider the coexistence of CDW and SDW. We propose a model of the mixed density wave, where CDW exists with antiferromagnetically coupled canting spins.

  9. Thermal effects on photogeneration of free carriers in organic conductors

    Science.gov (United States)

    de Oliveira Neto, Pedro H.; da Cunha, Wiliam F.; Roncaratti, Luiz F.; Gargano, Ricardo; Silva, Geraldo M. e.

    2010-06-01

    We performed numerical simulations of two parallel interacting conjugated polymer chains subjected to photoionization. Within the SSH model modified to include thermal effects, an electron is removed from one chain and later absorbed by the other chain. It was obtained that the system relaxes into a free polaron in each chain. For higher electron absorption the system initially relaxes into a pair of half-polarons that spontaneously suffers monomolecular recombination. The time response of the system agrees with experimental results. Although thermal effects are important to carrier creation mechanism, the obtained photogeneration creation time is temperature independent, as suggested experimentally.

  10. Study on detinning process of a reflow conductor roll

    Institute of Scientific and Technical Information of China (English)

    FU Hanguang; DAI Mingshan; FU Hanfeng

    2005-01-01

    Adhering tin is the main reason of a reflow conductor roll which works in an electroplating tin line (ETL). A detinning agent whose main composition is NaOH and KOH and assistant composition is Na2PbO2 or K2PbO2 and NaNO3 or NaNO2 has excellent detinning effects when the temperature of detinning solution is 40-80℃ and the temperature of the reflow conductor roll reaches 40-70℃. After the adhering tin layer of the reflow conductor roll is removed, the roughness of the reflow conductor roll can resume to 4.0 μm, its service life increases by 80%, and the repairing cost decreases by 90%.

  11. Casimir Free Energy at High Temperatures: Grounded vs Isolated Conductors

    CERN Document Server

    Fosco, C D; Mazzitelli, F D

    2016-01-01

    We evaluate the difference between the Casimir free energies corresponding to either grounded or isolated perfect conductors, at high temperatures. We show that a general and simple expression for that difference can be given, in terms of the electrostatic capacitance matrix for the system of conductors. For the case of close conductors, we provide approximate expressions for that difference, by evaluating the capacitance matrix using the proximity force approximation. Since the high-temperature limit for the Casimir free energy for a medium described by a frequency-dependent conductivity diverging at zero frequency coincides with that of an isolated conductor, our results may shed light on the corrections to the Casimir force in the presence of real materials.

  12. High voltage switches having one or more floating conductor layers

    Energy Technology Data Exchange (ETDEWEB)

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  13. Numerical analysis of quench in coated conductors with defects

    Science.gov (United States)

    Liu, Wenbin; Yong, Huadong; Zhou, Youhe

    2016-09-01

    When the superconductor is subjected to local thermal perturbations, a large amount of joule heat may be generated in the conductor, which may lead to a quench. In a quench event, a normal zone irreversibly spreads throughout the conductor leading to failure of the superconducting device. In this paper, we will discuss the one-dimensional quench behavior in the coated conductors with internal defects or interface defects. Based on the numerical procedure given in the previous works, the normal zone propagation is studied by using the finite difference method. The numerical results are presented to discuss the normal zone propagation. We consider the effect of internal defect on the nonuniform temperature propagation. For the conductor with interface defects, it can be found that the normal zone propagation velocity is increased by defects.

  14. Numerical analysis of quench in coated conductors with defects

    Directory of Open Access Journals (Sweden)

    Wenbin Liu

    2016-09-01

    Full Text Available When the superconductor is subjected to local thermal perturbations, a large amount of joule heat may be generated in the conductor, which may lead to a quench. In a quench event, a normal zone irreversibly spreads throughout the conductor leading to failure of the superconducting device. In this paper, we will discuss the one-dimensional quench behavior in the coated conductors with internal defects or interface defects. Based on the numerical procedure given in the previous works, the normal zone propagation is studied by using the finite difference method. The numerical results are presented to discuss the normal zone propagation. We consider the effect of internal defect on the nonuniform temperature propagation. For the conductor with interface defects, it can be found that the normal zone propagation velocity is increased by defects.

  15. A microstructure continuum approach to electromagneto-elastic conductors

    Science.gov (United States)

    Romeo, Maurizio

    2016-11-01

    A micromorphic continuum model of a deformable electromagnetic conductor is established introducing microdensities of bound and free charges. The conductive part of electric current consists of contributions due to free charges and microdeformation. Beside the conservation of charge, we derive suitable evolution equations for electric multipoles which are exploited to obtain the macroscopic form of Maxwell's equations. A constitutive model for electromagneto-elastic conductors is considered which allows for a natural characterization of perfect conductors independently on the form of the constitutive equation for the conduction current. A generalized Ohm's law is also derived for not ideal conductors which accounts for relaxation effects. The consequences of the linearized Ohm's law on the classic magnetic transport equation are shown.

  16. Electron transport in a mesoscopic superconducting ferromagnetic hybrid conductor

    Energy Technology Data Exchange (ETDEWEB)

    Giroud, M.; Hasselbach, K.; Courtois, H.; Pannetier, B. [Centre de Recherche sur les Tres Basses Temperatures, CNRS, 38 - Grenoble (France); Mailly, D. [Laboratoire de Photonique et de Nanostructures, 91 - Marcoussis (France)

    2003-01-01

    We present electrical transport experiments performed on submicron hybrid devices made of a ferromagnetic conductor (Co) and a superconducting (Al) electrode. The sample was patterned in order to separate the contributions of the Co conductor and of the Co-Al interface. We observed a strong influence of the Al electrode superconductivity on the resistance of the Co conductor. This effect is large only when the interface is highly transparent. We characterized the dependence of the observed resistance decrease on temperature, bias current and magnetic field. As the differential resistance of the ferromagnet exhibits a non-trivial asymmetry, we claim that the magnetic domain structure plays an important role in the electron transport properties of superconducting / ferromagnetic conductors. (authors)

  17. New resistivity for high-mobility quantum Hall conductors

    Science.gov (United States)

    Mceuen, P. L.; Szafer, A.; Richter, C. A.; Alphenaar, B. W.; Jain, J. K.

    1990-01-01

    Measurements showing dramatic nonlocal behavior in the four-terminal resistances of a high-mobility quantum Hall conductor are presented. These measurements illustrate that the standard definition of the resistivity tensor is inappropriate, but they are in excellent agreement with a new model of the conductor that treats the edge and bulk conducting pathways independently. This model uses a single intensive parameter, analogous to a local resistivity for the bulk channel only, to characterize the system.

  18. Guanidinium nonaflate as a solid-state proton conductor

    DEFF Research Database (Denmark)

    Chen, Xiaoli; Tang, Haolin; Putzeys, Tristan

    2016-01-01

    Protic organic ionic plastic crystals (POIPCs) are a type of novel solid-state proton conductors. In this work, guanidinium nonaflate ([Gdm-H][NfO]) is reported to be a model POIPC. Its structure-property relationship has been investigated comprehensively. Infrared analysis of [Gdm-H][NfO] and its...... deuterated analogue [Gdm-D][NfO] confirms the complete formation of the protic salts. The cations in as-prepared [Gdm-D][NfO] are estimated to consist of [C(ND2)2(NHD)]+ and [C(ND2)3]+ with a molar ratio of around 1:1. The deuteration also proves that each guanidinium cation has six displaceable protons...... order in the plastic crystalline phases. Dielectric spectroscopy measurements show that its ionic conductivity reaches 2.1 × 10-3 S cm-1 at 185 °C. The proton conduction in the plastic crystalline phases of [Gdm-H][NfO] is assumed to happen via the vehicle mechanism. In the molten state, the proton...

  19. Diamagnetic phase transitions in two-dimensional conductors

    Science.gov (United States)

    Bakaleinikov, L. A.; Gordon, A.

    2014-11-01

    A theory describing the susceptibility amplitude and the magnetic induction bifurcation near the dHvA driven diamagnetic phase transitions in quasi two-dimensional (2D) organic conductors of the (ET)2X with X=Cu(NCS)2, KHg(SCN)4, I3, AuBr2, IBr2, etc. is presented. We show that there is a drastic increase in the temperature and magnetic field dependence of the susceptibility amplitude on approaching the diamagnetic phase transition point. Near the phase transition point the temperature and magnetic field dependences are fitted by the ones typical of the mean-field phase transition theory. These dependences confirm the long-range character of the magnetic interactions among the conduction electrons leading to diamagnetic phase transitions. We demonstrate that the magnetic induction splitting of nuclear magnetic resonance (NMR) and muon spin-rotation spectroscopy (μSR) lines due to two Condon domains decreases tending to zero on approaching the diamagnetic phase transition. This decrease is fitted by the temperature and magnetic field dependence of the susceptibility characteristic of the mean-field theory of phase transitions. Performing new susceptibility, NMR and μSR experiments will enable to detect diamagnetic phase transitions and Condon domains in quasi 2D metals.

  20. Modelling the transient emission from a twin conductor cable

    Directory of Open Access Journals (Sweden)

    Ian Brook Darney

    2016-03-01

    Full Text Available Using the equations of transmission line theory, a programme is developed to simulate the response of an open-circuit line to a step pulse. This is compared with the observed response of a twin-conductor cable. It is deduced that not all of the current delivered to the send conductor arrives back via the return conductor. Some of it departs in the form of radiated emission. A virtual capacitor is used to simulate this, with limited success. However, by adding a second virtual capacitor to simulate transient current being delivered from the return conductor back to the send conductor, a fair correlation is achieved between theoretical and actual results. This analysis demonstrates that the return conductor plays an active role in propagating any signal along the cable. This study also demonstrates that a circuit model can be created to simulate the mechanisms involved in the radiation of interference from power supply cables. This is but one example of the use of circuit models to analyse electromagnetic interference (EMI. The key relationship between electromagnetic theory and circuit theory which enables this technique to be used to analyse any EMI problem is identified. A dramatic simplification in the mathematics can be achieved.

  1. Electron quantum optics in ballistic chiral conductors

    Energy Technology Data Exchange (ETDEWEB)

    Bocquillon, Erwann; Freulon, Vincent; Parmentier, Francois D.; Berroir, Jean-Marc; Placais, Bernard; Feve, Gwendal [Laboratoire Pierre Aigrain, Ecole Normale Superieure, CNRS (UMR 8551), Universite Pierre et Marie Curie, Universite Paris Diderot, Paris (France); Wahl, Claire; Rech, Jerome; Jonckheere, Thibaut; Martin, Thierry [Aix Marseille Universite, CNRS, CPT, UMR 7332, Marseille (France); Universite de Toulon, CNRS, CPT, UMR 7332, La Garde (France); Grenier, Charles; Ferraro, Dario; Degiovanni, Pascal [Universite de Lyon, Federation de Physique Andre Marie Ampere, CNRS - Laboratoire de Physique de l' Ecole Normale Superieure de Lyon, Lyon (France)

    2014-01-15

    The edge channels of the quantum Hall effect provide one dimensional chiral and ballistic wires along which electrons can be guided in an optics-like setup. Electronic propagation can then be analyzed using concepts and tools derived from optics. After a brief review of electron optics experiments performed using stationary current sources which continuously emit electrons in the conductor, this paper focuses on triggered sources, which can generate on-demand a single particle state. It first outlines the electron optics formalism and its analogies and differences with photon optics and then turns to the presentation of single electron emitters and their characterization through the measurements of the average electrical current and its correlations. This is followed by a discussion of electron quantum optics experiments in the Hanbury-Brown and Twiss geometry where two-particle interferences occur. Finally, Coulomb interactions effects and their influence on single electron states are considered. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Internally heated convection beneath a poor conductor

    CERN Document Server

    Goluskin, David

    2016-01-01

    We consider convection in an internally heated layer of fluid that is bounded below by a perfect insulator and above by a poor conductor. The poorly conducting boundary is modelled by a fixed heat flux. Using solely analytical methods, we find linear and energy stability thresholds for the static state, and we construct a lower bound on the mean temperature that applies to all flows. The linear stability analysis yields a Rayleigh number above which the static state is linearly unstable ($R_L$), and the energy analysis yields a Rayleigh number below which it is globally stable ($R_E$). For various boundary conditions on the velocity, exact expressions for $R_L$ and $R_E$ are found using long-wavelength asymptotics. Each $R_E$ is strictly smaller than the corresponding $R_L$ but is within 1%. The lower bound on the mean temperature is proven for no-slip velocity boundary conditions using the background method. The bound guarantees that the mean temperature of the fluid, relative to that of the top boundary, gr...

  3. The ATLAS SemiConductorTracker

    CERN Document Server

    Mikuz, M

    2004-01-01

    The ATLAS SemiConductor Tracker (SCT) is presented. About 16000 silicon micro-strip sensors with a total active surface of over 60 m /sup 2/ and with 6.3 million read-out channels are built into 4088 modules arranged into four barrel layers and nine disks covering each of the forward regions up to an eta of 2.5. Challenges are imposed by the hostile radiation environment with particle fluences up to 2*10 /sup 14/ cm/sup -2/ 1 MeV neutron NIEL equivalent and 100 kGy TID, the 25 ns LHC bunch crossing time and the need for a hermetic, lightweight tracker. The solution adopted is carefully designed strip detectors operated at -7 degrees C, biased up to 500 V and read out by binary rad-hard fast BiCMOS electronics. A zero-CTE carbon fibre structure provides mechanical support. 30 kW of power are supplied on aluminium/Kapton tapes and cooled by C/sub 3/F/sub 8/ evaporative cooling. Data and commands are transferred by optical links. Prototypes of detector modules have been built, irradiated to the maximum expected ...

  4. Local electron heating in nanoscopic conductors

    Science.gov (United States)

    D'Agosta, Roberto; Sai, Na; di Ventra, Massimiliano

    2007-03-01

    The electron current density in nanoscale junctions is typically several orders of magnitude larger than the corresponding one in bulk electrodes. Consequently, the electron-electron scattering rate increases substantially in the junction. This leads to local electron heating of the underlying Fermi sea [1] in analogy to the local ionic heating that is due to the increased electron-phonon scattering rates [2]. By using a novel hydrodynamic formulation of transport [3], we predict the bias dependence of local electron heating in quasi-ballistic nanoscale conductors [1], its effect on ionic heating [1], and the consequent observable changes in the inelastic conductance [4]. [1] R. D'Agosta, N. Sai and M. Di Ventra, accepted in Nano Letters (2006). [2] Y.-C. Chen, M. Zwolak, and M. Di Ventra, Nano Lett. 3, 1961 (2003); Nano Lett. 4, 1709 (2004); Nano Lett. 5, 621 (2005). M. J. Montgomery, T. N. Todorov, and A. P. Sutton, J. Phys. Cond. Matt. 14, 5377 (2002). [3] R. D'Agosta and M. Di Ventra, J. Phys. Cond. Matt. in press. [4] R. D'Agosta and M. Di Ventra, in preparation.

  5. On electromagnetic induction in electric conductors

    CERN Document Server

    Korolev, Alexander I

    2013-01-01

    Experimental validation of the Faraday's law of electromagnetic induction (EMI) is performed when an electromotive force is generated in thin copper turns, located inside a large magnetic coil. It has been established that the electromotive force (emf) value should be dependent not only on changes of the magnetic induction flux through a turn and on symmetry of its crossing by magnetic power lines also. The law of EMI is applicable in sufficient approximation in case of the changes of the magnetic field near the turn are symmetrical. Experimental study of the induced emf in arcs and a direct section of the conductor placed into the variable field has been carried out. Linear dependence of the induced emf on the length of the arc has been ascertained in case of the magnetic field distribution symmetry about it. Influence of the magnetic field symmetry on the induced emf in the arc has been observed. The curve of the induced emf in the direct section over period of current pulse is similar to this one for the t...

  6. SYNTHESIS AND CHARACTERIZATION OF PROTON CONDUCTORS

    Energy Technology Data Exchange (ETDEWEB)

    Brinkman, K.

    2010-02-18

    The morphological and electrical properties of yttrium (Y) and indium (In) doped barium cerate perovskites of the form BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} (with x=0-0.3) prepared by a modified Pechini method were investigated as potential high temperature proton conductors with improved chemical stability. The sinterability increased with the increase of In-doping, and the perovskite phase was found in the BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} solid solutions over the range 0 {le} x {le} 0.3. The conductivities decreased (from x to x, insert quantitative values) while the tolerance to wet CO{sub 2} improved for BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} samples with an increase of In-doping.

  7. Depletion region effect of highly efficient hole conductor free CH3NH3PbI3 perovskite solar cells.

    Science.gov (United States)

    Aharon, Sigalit; Gamliel, Shany; El Cohen, Bat; Etgar, Lioz

    2014-06-14

    The inorganic-organic perovskite is currently attracting a lot of attention due to its use as a light harvester in solar cells. The large absorption coefficients, high carrier mobility and good stability of organo-lead halide perovskites present good potential for their use as light harvesters in mesoscopic heterojunction solar cells. This work concentrated on a unique property of the lead halide perovskite, its function simultaneously as a light harvester and a hole conductor in the solar cell. A two-step deposition technique was used to optimize the perovskite deposition and to enhance the solar cell efficiency. It was revealed that the photovoltaic performance of the hole conductor free perovskite solar cell is strongly dependent on the depletion layer width which was created at the TiO2-CH3NH3PbI3 junction. X-ray diffraction measurements indicate that there were no changes in the crystallographic structure of the CH3NH3PbI3 perovskite over time, which supports the high stability of these hole conductor free perovskite solar cells. Furthermore, the power conversion efficiency of the best cells reached 10.85% with a fill factor of 68%, a Voc of 0.84 V, and a Jsc of 19 mA cm(-2), the highest efficiency to date of a hole conductor free perovskite solar cell.

  8. Synergistic, ultrafast mass storage and removal in artificial mixed conductors

    Science.gov (United States)

    Chen, Chia-Chin; Fu, Lijun; Maier, Joachim

    2016-08-01

    Mixed conductors—single phases that conduct electronically and ionically—enable stoichiometric variations in a material and, therefore, mass storage and redistribution, for example, in battery electrodes. We have considered how such properties may be achieved synergistically in solid two-phase systems, forming artificial mixed conductors. Previously investigated composites suffered from poor kinetics and did not allow for a clear determination of such stoichiometric variations. Here we show, using electrochemical and chemical methods, that a melt-processed composite of the ‘super-ionic’ conductor RbAg4I5 and the electronic conductor graphite exhibits both a remarkable silver excess and a silver deficiency, similar to those found in single-phase mixed conductors, even though such behaviour is not possible in the individual phases. Furthermore, the kinetics of silver uptake and release is very fast. Evaluating the upper limit set by interfacial ambipolar diffusion reveals chemical diffusion coefficients that are even higher than those achieved for sodium chloride in bulk liquid water. These results could potentially stimulate systematic research into powerful, even mesoscopic, artificial mixed conductors.

  9. Design of force-cooled conductors for large fusion magnets

    Energy Technology Data Exchange (ETDEWEB)

    Dresner, L.; Lue, J.W.

    1977-01-01

    Conductors cooled by supercritical helium in forced convection are under active consideration for large toroidal fusion magnets. One of the central problems in designing such force cooled conductors is to maintain an adequate stability margin while keeping the pumping power tolerably low. A method has been developed for minimizing the pumping power for fixed stability by optimally choosing the matrix-to-superconductor and the metal-to-helium ratios. Such optimized conductors reduce pumping power requirements for fusion size magnets to acceptable limits. Furthermore, the mass flow and hence pumping losses can be varied through a magnet according to the local magnetic field and magnitude of desired stability margin. Force cooled conductors give flexibility in operation, permitting, for example, higher fields to be obtained than originally intended by lowering the bath temperature or increasing the pumping power or both. This flexibility is only available if the pumping power is low to begin with. Scaling laws for the pumping requirement and stability margin as functions of operating current density, number of strands and such physical parameters as stabilizer resistivity and critical current density, have been proved. Numerical examples will be given for design of conductors intended for use in large toroidal fusion magnet systems.

  10. The fate of sounds in conductors' brains: an ERP study.

    Science.gov (United States)

    Nager, Wido; Kohlmetz, Christine; Altenmüller, Eckart; Rodriguez-Fornells, Antoni; Münte, Thomas F

    2003-06-01

    Professional music conductors are required to home in on a particular musician but at the same time have to monitor the entire orchestra. It was hypothesized that this unique experience should be reflected by superior auditory spatial processing. Event-related brain potentials were obtained, while conductors, professional pianists, and non-musicians listened to sequences of bandpass-filtered noise-bursts presented in random order from six speakers, three located in front and three to the right of the subjects. In different runs, subjects either attended the centermost or the most peripheral speaker in order to detect slightly deviant noise-bursts. For centrally located speakers, the ERPs showed a typical Nd attention effect for the relevant location with a steep decline for the neighboring speakers in all subject groups. For peripheral speakers, only the conductors showed attentional selectivity, while the Nd effect was of similar size for all three peripheral speakers in the other two groups. These ERP effects were paralleled by an enhanced behavioral selectivity in peripheral auditory space in conductors. Moreover, the pre-attentive monitoring of the entire auditory scene indexed by the mismatch negativity was superior in musicians compared to non-musicians. In conductors, the MMN was followed by a positivity suggesting an attention shift towards the deviant stimuli in this group only.

  11. Hearing status among Norwegian train drivers and train conductors.

    Science.gov (United States)

    Lie, A; Skogstad, M; Johnsen, T S; Engdahl, B; Tambs, K

    2013-12-01

    There is a general perception that train drivers and conductors may be at increased risk of developing noise-induced hearing loss. To study job-related hearing loss among train drivers and train conductors. Audiograms from train drivers and train conductors were obtained from the medical records of the occupational health service of the major Norwegian railway company. The results were compared with audiograms from an internal control group of railway workers and an external reference group of people not occupationally exposed to noise. The monaural hearing threshold level at 4kHz, the mean binaural value at 3, 4 and 6kHz and the prevalence of audiometric notches (≥25 dB at 4kHz) were used for comparison. Audiograms were available for 1567 drivers, 1565 conductors, 4029 railway worker controls and 15 012 people not occupationally exposed to noise. No difference in hearing level or prevalence of audiometric notches was found between study groups after adjusting for age and gender. Norwegian train drivers and conductors have normal hearing threshold levels comparable with those in non-exposed groups.

  12. Research on the electronic and optical properties of polymer and other organic molecular thin films

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-02-01

    The main goal of the work is to find materials and methods of optimization of organic layered electroluminescent cells and to study such properties of polymers and other organic materials that can be used in various opto-electronic devices. The summary of results obtained during the first year of work is presented. They are: (1) the possibility to produce electroluminescent cells using a vacuum deposition photoresist technology for commercial photoresists has been demonstrated; (2) the idea to replace the polyaryl polymers by other polymers with weaker hole conductivity for optimization of electroluminescent cells with ITO-Al electrodes has been suggested. The goal is to obtain amorphous processable thin films of radiative recombination layers in electroluminescent devices; (3) procedures of preparation of high-quality vacuum-deposited poly (p-phenylene) (PPP) films on various substrates have been developed; (4) it was found for the first time that the fluorescence intensity of PPP films depends on the degree of polymerization; (5) the role of interfaces between organic compounds, on one side, and metals or semiconductors, on the other side, has been studied and quenching of the fluorescence caused by semiconductor layer in thin sandwiches has been observed; (6) studies of the dynamics of photoexcitations revealed the exciton self-trapping in quasi-one-dimensional aggregates; and (7) conditions for preparation of highly crystalline fullerene C{sub 60} films by vacuum deposition have been found. Composites of C{sub 60} with conjugated polymers have been prepared.

  13. Loss and Inductance Investigation in Superconducting Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Tønnesen, Ole; Træholt, Chresten

    1999-01-01

    An important parameter in the design and optimization of a superconducting cable conductor is the control of the current distribution among single tapes and layers. This distribution is to a large degree determined by inductances, since the resistances are low. The self and mutual inductances...... of the layers are therefore studied theoretically. The current distribution between the superconducting layers is monitored as a function of transport current, and the results are compared with the expected current distribution given by our electrical circuit model.The AC-losses are measured as a function...... of transport current and current distribution.This presentation is based on a number of experiments performed on prototype superconducting cable conductors. The critical current (1uV/cm) of the conductor at 77K was 1590 A (cable #1) and 3240 A (cable #2) respectively.At an rms current of 2 kA (50 Hz) the AC...

  14. The Joule-Thomson effect on the thermoelectric conductors

    Energy Technology Data Exchange (ETDEWEB)

    Consiglieri, Luisa [Lisbon Univ. (Portugal). Dept. of Mathematics and CMAF

    2009-03-15

    The transmission of an electric current in a conductor is a process in which some electrical energy is converted into heat (thermal energy). We deal with a nonlinear boundary value elliptic problem which describes the electrical heating of a solid conductor and the Joule-Thomson effect is taken into account. The existence of a weak solution is proved under both space and temperature dependence of the electrical and thermal conductivities. When the coefficients are only dependent on their temperature argument, some regularity results are stated. (orig.)

  15. Improvement of SOFC electrodes using mixed ionic-electronic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Y.; Hishinuma, M. [Tokyo Gas Co., Ltd. (Japan)

    1996-12-31

    Since the electrode reaction of SOFC is limited to the proximity of a triple phase boundary (TPB), the local current density at the electrode and electrolyte interface is larger than mean current density, which causes large ohmic and electrode polarization. This paper describes an application of mixed ionic-electronic conductors to reduce such polarization by means of (1) enhancing ionic conductivity of the electrolyte surface layer by coating a high ionic conductors, and (2) reducing the local current density by increasing the electrochemically active sites.

  16. Effects of room-temperature tensile fatigue on critical current and n-value of IBAD-MOCVD YBa2Cu3O7-x /Hastelloy coated conductor

    Science.gov (United States)

    Rogers, Samuel; Kan Chan, Wan; Schwartz, Justin

    2016-08-01

    REBa2Cu3O7-x (REBCO) coated conductors potentially enable a multitude of superconducting applications, over a wide range of operating temperatures and magnetic fields, including high-field magnets, energy storage devices, motors, generators, and power transmission systems (Zhang et al 2013 IEEE Trans. Appl. Supercond. 23 5700704). Many of these are AC applications and thus the fatigue properties may be limiting (Vincent et al 2013 IEEE Trans. Appl. Supercond. 23 5700805). Previous electromechanical studies have determined the performance of REBCO conductors under single cycle loads (Barth et al 2015 Supercond. Sci. Technol. 28 045011), but an understanding of the fatigue properties is lacking. Here the fatigue behavior of commercial ion beam assisted deposition-metal organic chemical vapor deposition REBCO conductors on Hastelloy substrates is reported for axial tensile strains up to 0.5% and up to 100 000 cycles. Failure mechanisms are investigated via microstructural studies. Results show that REBCO conductors retained I c(ɛ)/I c0 = 0.9 for 10 000 cycles at ɛ = 0.35% and ɛ = 0.45% strain, and ɛ = 0.5% for 100 cycles. The main cause of fatigue degradation in REBCO conductors is crack propagation that initiates at the slitting defects that result from the manufacturing process.

  17. Enhancing Light-Trapping Properties of Amorphous Si Thin-Film Solar Cells Containing High-Reflective Silver Conductors Fabricated Using a Nonvacuum Process

    Directory of Open Access Journals (Sweden)

    Jun-Chin Liu

    2014-01-01

    Full Text Available We proposed a low-cost and highly reflective liquid organic sheet silver conductor using back contact reflectors in amorphous silicon (a-Si single junction superstrate configuration thin-film solar cells produced using a nonvacuum screen printing process. A comparison of silver conductor samples with vacuum-system-sputtered silver samples indicated that the short-circuit current density (Jsc of sheet silver conductor cells was higher than 1.25 mA/cm2. Using external quantum efficiency measurements, the sheet silver conductor using back contact reflectors in cells was observed to effectively enhance the light-trapping ability in a long wavelength region (between 600 nm and 800 nm. Consequently, we achieved an optimal initial active area efficiency and module conversion efficiency of 9.02% and 6.55%, respectively, for the a-Si solar cells. The results indicated that the highly reflective sheet silver conductor back contact reflector layer prepared using a nonvacuum process is a suitable candidate for high-performance a-Si thin-film solar cells.

  18. Study on Quench Protection of a Coil Wound of YBCO Coated Conductors

    Institute of Scientific and Technical Information of China (English)

    FUYoukun

    2003-01-01

    Owing to recent progress of long YBCO coated conductors, coils wound of YBCO conductors will be developed in near future.Compared with coils wound of LTS conductom, coils wound of HTS conductors operated at higher temperature are hard to be quenched. However, measures for quench protection are still necessary. Especially YBCO coated conductors that are made by deposition of thin YBCO film on Ni based alloy substrates such as Hastelloy tapes are highly resistive when they are quenched, Therefore,

  19. 30 CFR 57.12005 - Protection of power conductors from mobile equipment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of power conductors from mobile... NONMETAL MINES Electricity Surface and Underground § 57.12005 Protection of power conductors from mobile equipment. Mobile equipment shall not run over power conductors, nor shall loads be dragged over...

  20. 30 CFR 57.12069 - Lightning protection for telephone wires and ungrounded conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lightning protection for telephone wires and ungrounded conductors. 57.12069 Section 57.12069 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... ungrounded conductors. Each ungrounded conductor or telephone wire that leads underground and is...

  1. 30 CFR 77.508 - Lightning arresters, ungrounded and exposed power conductors and telephone wires.

    Science.gov (United States)

    2010-07-01

    ... power conductors and telephone wires. 77.508 Section 77.508 Mineral Resources MINE SAFETY AND HEALTH... arresters, ungrounded and exposed power conductors and telephone wires. All ungrounded, exposed power conductors and telephone wires shall be equipped with suitable lightning arresters which are...

  2. 30 CFR 56.12069 - Lightning protection for telephone wires and ungrounded conductors.

    Science.gov (United States)

    2010-07-01

    ... ungrounded conductors. 56.12069 Section 56.12069 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... NONMETAL MINES Electricity § 56.12069 Lightning protection for telephone wires and ungrounded conductors. Each ungrounded power conductor or telephone wire that leads underground and is directly exposed...

  3. 30 CFR 75.521 - Lightning arresters; ungrounded and exposed power conductors and telephone wires.

    Science.gov (United States)

    2010-07-01

    ... power conductors and telephone wires. 75.521 Section 75.521 Mineral Resources MINE SAFETY AND HEALTH... Electrical Equipment-General § 75.521 Lightning arresters; ungrounded and exposed power conductors and telephone wires. Each ungrounded, exposed power conductor and each ungrounded, exposed telephone wire...

  4. 30 CFR 75.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

    Science.gov (United States)

    2010-07-01

    ... conduits enclosing power conductors. 75.700 Section 75.700 Mineral Resources MINE SAFETY AND HEALTH... Grounding § 75.700 Grounding metallic sheaths, armors, and conduits enclosing power conductors. All metallic sheaths, armors, and conduits enclosing power conductors shall be electrically continuous throughout...

  5. 30 CFR 57.12010 - Isolation or insulation of communication conductors.

    Science.gov (United States)

    2010-07-01

    ... conductors. 57.12010 Section 57.12010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... conductors. Telephone and low-potential signal wire shall be protected, by isolation or suitable insulation, or both, from contacting energized power conductors or any other power source....

  6. 30 CFR 77.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

    Science.gov (United States)

    2010-07-01

    ... conduits enclosing power conductors. 77.700 Section 77.700 Mineral Resources MINE SAFETY AND HEALTH..., and conduits enclosing power conductors. Metallic sheaths, armors, and conduits enclosing power conductors shall be electrically continuous throughout and shall be grounded by methods approved by...

  7. 30 CFR 75.1002 - Installation of electric equipment and conductors; permissibility.

    Science.gov (United States)

    2010-07-01

    ... conductors; permissibility. 75.1002 Section 75.1002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Wires and Trolley Feeder Wires § 75.1002 Installation of electric equipment and conductors... equipment is located within 150 feet of pillar workings or longwall faces. (b) Electric conductors...

  8. Application Research on Drag Reduced Conductors for Electric Power Transmission Lines in Strong Wind Areas

    Directory of Open Access Journals (Sweden)

    Li Dong Qing

    2016-01-01

    Full Text Available The breeze vibration duration of conductors is long, the vibration amplitude is strong and the frequency range is wide for electric power transmission lines in strong wind areas, which seriously affects the safe and stable operation of transmission lines. There are two design schemes of conductors which can achieve the purpose of reducing wind-induced disaster. One is enhancing the structural strength of conductors to withstand wind load, but the investment is enormous and the effect is limited. The other is developing drag reduced conductors to reduce wind load by changing conductor structure. This paper started from application feasibility analysis of drag reduced conductors and designed four drag reduced conductors by structure optimization of the conventional aluminium conductor steel reinforced JL/G1A-630/45-45/7, denoted as DFY630/45(45°-R3.5, DFY630/45(60°-R3.5, DFY630/45(45°–R3.2 and DFY630/45(60°-R3.2, respectively. The wind tunnel test was performed and the wind resistance coefficients in unit length of five conductors were compared. Result showed that the wind resistance coefficients in unit length of four drag reduced conductors were obviously lower than that of the conventional conductor. By controlling the manufacturing process, popularization and application of drag reduced conductors for transmission lines in strong wind areas can be realized.

  9. Low-frequency scattering from two-dimensional perfect conductors

    DEFF Research Database (Denmark)

    Hansen, Thorkild; Yaghjian, A.D

    1991-01-01

    Exact expressions have been obtained for the leading terms in the low-frequency expansions of the far fields scattered from three different types of two-dimensional perfect conductors: a cylinder with finite cross section, a cylindrical bump on an infinite ground plane, and a cylindrical dent...

  10. Solutions of Maxwell equations for hollow curved wave conductor

    CERN Document Server

    Bashkov, V I

    1995-01-01

    In the present paper the idea is proposed to solve Maxwell equations for a curved hollow wave conductor by means of effective Riemannian space, in which the lines of motion of fotons are isotropic geodesies for a 4-dimensional space-time. The algorithm of constructing such a metric and curvature tensor components are written down explicitly. The result is in accordance with experiment.

  11. Effects of volume conductor and source configuration on simulated magnetogastrograms

    Energy Technology Data Exchange (ETDEWEB)

    Komuro, Rie; Qiao Wenlian; Pullan, Andrew J; Cheng, Leo K, E-mail: l.cheng@auckland.ac.n [Auckland Bioengineering Institute, University of Auckland, Auckland (New Zealand)

    2010-11-21

    Recordings of the magnetic fields (MFs) arising from gastric electrical activity (GEA) have been shown to be able to distinguish between normal and certain abnormal GEA. Mathematical models provide a powerful tool for revealing the relationship between the underlying GEA and the resultant magnetogastrograms (MGGs). However, it remains uncertain the relative contributions that different volume conductor and dipole source models have on the resultant MFs. In this study, four volume conductor models (free space, sphere, half space and an anatomically realistic torso) and two dipole source configurations (containing 320 moving dipole sources and a single equivalent moving dipole source) were used to simulate the external MFs. The effects of different volume conductor models and dipole source configurations on the MF simulations were examined. The half space model provided the best approximation of the MFs produced by the torso model in the direction normal to the coronal plane. This was despite the fact that the half space model does not produce secondary sources, which have been shown to contribute up to 50% of the total MFs when an anatomically realistic torso model was used. We conclude that a realistic representation of the volume conductor and a detailed dipole source model are likely to be necessary when using a model-based approach for interpreting MGGs.

  12. Conductor and Ensemble Performance Expressivity and State Festival Ratings

    Science.gov (United States)

    Price, Harry E.; Chang, E. Christina

    2005-01-01

    This study is the second in a series examining the relationship between conducting and ensemble performance. The purpose was to further examine the associations among conductor, ensemble performance expressivity, and festival ratings. Participants were asked to rate the expressivity of video-only conducting and parallel audio-only excerpts from a…

  13. Influence of the magnetic field profile on ITER conductor testing

    NARCIS (Netherlands)

    Nijhuis, A.; Ilyin, Y.; Kate, ten H.H.J.

    2006-01-01

    We performed simulations with the numerical CUDI-CICC code on a typical short ITER (International Thermonuclear Experimental Reactor) conductor test sample of dual leg configuration, as usually tested in the SULTAN test facility, and made a comparison with the new EFDA-Dipole test facility offering

  14. Center conductor diagnostic for multipactor detection in inaccessible geometries

    Science.gov (United States)

    Chaplin, Vernon H.; Hubble, Aimee A.; Clements, Kathryn A.; Graves, Timothy P.

    2017-01-01

    Electron collecting current probes are the most reliable diagnostic of multipactor and radiofrequency (RF) ionization breakdown; however, stand-alone probes can only be used in test setups where the breakdown region is physically accessible. This paper describes techniques for measuring multipactor current directly on the center conductor of a coaxial RF device (or more generally, on the signal line in any two-conductor RF system) enabling global multipactor detection with improved sensitivity compared to other common diagnostics such as phase null, third harmonic, and reflected power. The center conductor diagnostic may be AC coupled for use in systems with a low DC impedance between the center conductor and ground. The effect of DC bias on the breakdown threshold was studied: in coaxial geometry, the change in threshold was positive biases satisfying VD C/VR F 0 effectively with no bias at all—this is the preferred implementation, but biases in the range VD C=0 -10 V may be applied if necessary. The polarity of the detected current signal may be positive or negative depending on whether there is net electron collection or emission globally.

  15. Elementary charge-transfer processes in mesoscopic conductors

    NARCIS (Netherlands)

    Vanević, M.; Nazarov, Y.V.; Belzig, W.

    2008-01-01

    We determine charge-transfer statistics in a quantum conductor driven by a time-dependent voltage and identify the elementary transport processes. At zero temperature unidirectional and bidirectional single-charge transfers occur. The unidirectional processes involve electrons injected from the sour

  16. Polaron effects in the protonic conductor hydrogen uranyl phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Lupu, D. (Inst. of Isotopic and Molecular Technology, Cluj-Napoca (Romania)); Grecu, R. (Inst. of Chemistry, Cluj-Napoca (Romania)); Biris, A.R. (Inst. of Isotopic and Molecular Technology, Cluj-Napoca (Romania))

    1993-08-01

    The isotope effects on the conductivity of hydrogen uranyl phosphate reveal ionic polaron effects in this solid protonic conductor, in agreement with the small polaron theory. An absorption band is observed at 0.67 eV, which can be correlated with the conduction mechanism consisting in both tunnelling and over-barrier hopping processes. (orig.)

  17. Low resistive trasparent conductors with metallic grids : modeling and experiments

    NARCIS (Netherlands)

    Deelen, J. van; Rendering, H.; Mannetje, H.H 't; Klerk, L.; Hovestad, A.

    2012-01-01

    At present, transparent conducting oxides (TCOs) are still superior in performance to most other transparent conductors. Results on opto-electronic modeling and design optimization of TCOs are presented using a monolithically integrated CIGS cell configuration as case. For various cell dimensions an

  18. Metallic grids for low resistive transparent conductors: modeling and experiments

    NARCIS (Netherlands)

    Deelen, J. van; Rendering, H.; Mannetje, H. het; Klerk, L.; Hovestad, A.

    2012-01-01

    At present, transparent conducting oxides (TCOs) are still superior in performance to most other transparent conductors. Results on opto-electronic modeling and design optimization of TCOs are presented using a monolithically integrated CIGS cell configuration as case. For various cell dimensions an

  19. Attentional flexibility and memory capacity in conductors and pianists.

    Science.gov (United States)

    Wöllner, Clemens; Halpern, Andrea R

    2016-01-01

    Individuals with high working memory (WM) capacity also tend to have better selective and divided attention. Although both capacities are essential for skilled performance in many areas, evidence for potential training and expertise effects is scarce. We investigated the attentional flexibility of musical conductors by comparing them to equivalently trained pianists. Conductors must focus their attention both on individual instruments and on larger sections of different instruments. We studied students and professionals in both domains to assess the contributions of age and training to these skills. Participants completed WM span tests for auditory and visual (notated) pitches and timing durations, as well as long-term memory tests. In three dichotic attention tasks, they were asked to detect small pitch and timing deviations from two melodic streams presented in baseline (separate streams), selective-attention (concentrating on only one stream), and divided-attention (concentrating on targets in both streams simultaneously) conditions. Conductors were better than pianists in detecting timing deviations in divided attention, and experts detected more targets than students. We found no group differences for WM capacity or for pitch deviations in the attention tasks, even after controlling for the older age of the experts. Musicians' WM spans across multimodal conditions were positively related to selective and divided attention. High-WM participants also had shorter reaction times in selective attention. Taken together, conductors showed higher attentional flexibility in successfully switching between different foci of attention.

  20. Observation of magnetic Bragg peaks in quasi-one-dimensional antiferromagnet Cu{sub 6}Ge{sub 6}O{sub 18-x}D{sub 2}O (x = 0, 6)

    Energy Technology Data Exchange (ETDEWEB)

    Hase, Masashi; Terada, Noriki; Suzuki, Hiroyuki S; Kitazawa, Hideaki; Ozawa, Kiyoshi [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Kaneko, Koji; Metoki, Naoto; Matsuda, Masaaki; Kakurai, Kazuhisa, E-mail: HASE.Masashi@nims.go.j [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata Shirane, Tokai, Naka, Ibaraki 319-1195 (Japan)

    2009-03-01

    The cuprates Cu{sub 6}Ge{sub 6}O{sub 18-x}D{sub 2}O (x = 0, 6) have spin-1/2 chains with first-and second-nearest-neighbor (1NN and 2NN) antiferromagnetic (AF) exchange interactions. Magnetic long-range order (LRO) appears below 74 and 39 K for x = 0 and 6, respectively. We observed two magnetic Bragg peaks in each sample in neutron diffraction measurements on powder samples. These peaks indicate appearance of collinear AF LRO. We confirmed that both the 1NN interaction and nearest-neighbor interchain interaction were AF.

  1. Electrical resistivity and thermoelectric power of a quasi-one-dimensional Nb{sub 3}Te{sub 4} single crystal inserted with mercury: Hg{sub x}Nb{sub 3}Te{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kagohashi, Takanori; Takarada, Tukasa; Hasegawa, Hitoshi; Katumata, Yuriko; Kuga, Masanori; Okamoto, Hiroyuki; Kaneko, Hiroshi; Ishihara, Yutaka [Department of Physics, Faculty of Science, Kanazawa University, Kanazawa 920-1192 (Japan)

    1999-08-23

    The electrical resistivity and the thermoelectric power of Nb{sub 3}Te{sub 4} inserted with mercury have been measured in the temperature range from 1.4 to 300 K. The magnitude of the resistivity and the residual-resistivity ratio are not greatly affected by addition of Hg. The magnitude of the resistive anomaly at 90 K increases when adding a small amount of Hg but begins to decrease at about x=0.03 and is no longer visible at about x=0.15. Similarly, the magnitude of the resistive anomaly at 30 K decreases with increasing Hg concentration and disappears at about x=0.26. The thermoelectric power S also shows two anomalies at about 90 and 30 K. The anomaly of S at 90 K becomes smeared by addition of Hg and disappears at about x=0.3. The anomaly of S at 30 K becomes clear by addition of Hg and is still present at an amount of x=0.8. The sign of S is negative at all measured temperatures for x<0.3 and is positive at temperatures below 7 K for x>0.3. The superconducting transition temperature is enhanced from 1.9 to 5.4 K by addition of Hg. The upper critical fields parallel (H{sub c2parallel}) and perpendicular (H{sub c2} perpendicular) to the c axis have been measured near T{sub C}. The critical fields show large anisotropy for x{>=}0.3: the ratio H{sub c2parallel}/H{sub c2} perpendicular is about 5 for x<0.3 and 40 for x{>=}0.3. These results are discussed on the basis of the multiband model with electron-like and hole-like carriers and with phonon drag. (author)

  2. Characterization of the quasi-one-dimensional compounds δ-(EDT-TTF-CONMe{sub 2}){sub 2}X, X=AsF{sub 6} and Br by vibrational spectroscopy and density functional theory calculations

    Energy Technology Data Exchange (ETDEWEB)

    Peterseim, Tobias; Dressel, Martin [1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany); Antal, Ágnes [1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany); Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Batail, Patrick [Laboratoire MOLTECH, UMR 6200 CNRS-Université d' Angers, Bt. K, UFR Sciences, 2 Boulevard Lavoisier, F-49045 Angers (France); Drichko, Natalia [1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany); Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2014-02-14

    We have investigated the infrared spectra of the quarter-filled charge-ordered insulators δ-(EDT-TTF-CONMe{sub 2}){sub 2}X (X= AsF{sub 6}, Br) along all three crystallographic directions in the temperature range from 300 to 10 K. DFT-assisted normal mode analysis of the neutral and ionic EDT-TTF-CONMe{sub 2} molecule allows us to assign the experimentally observed intramolecular modes and to obtain relevant information on the charge ordering and intramolecular interactions. From frequencies of charge-sensitive vibrations we deduce that the charge-ordered state is already present at room temperature and does not change on cooling, in agreement with previous NMR measurements. The spectra taken along the stacking direction clearly show features of vibrational overtones excited due to the anharmonic electronic molecule potential caused by the large charge disproportionation between the molecular sites. The shift of certain vibrational modes indicates the onset of the structural transition below 200 K.

  3. High pressure synthesis and magnetic studies of quasi one dimensional systems Sr{sub n-1} Cu{sub n+1} O{sub 2n} (n=3,5)

    Energy Technology Data Exchange (ETDEWEB)

    Azuma, M.; Hiroi, Z.; Takano, M. [Kyoto Univ. (Japan)] [and others

    1994-12-31

    SrCu{sub 2}O{sub 3} and Sr{sub 2}Cu{sub 3}O{sub 5} containing two-leg and three-leg S=1/2 ladders made of antiferromagnetic Cu-O-Cu linear bonds, respectively, were synthesized at high pressure, and their crystallographic and magnetic properties were investigated. Both susceptibility and T{sub 1} data of NMR revealed the existence of a large spin gap only for SrCu{sub 2}O{sub 3}. Superconductivity, which had been predicted theoretically for carrier-doped SrCu{sub 2}O{sub 3} could not be realized although partial substitution of La{sup 3+} for Sr{sup 2+} seemed to be carried out successfully. Electron carriers injected seems to remain localized.

  4. Structure Design and Service Performance Study of Low Wind-pressure Conductor

    Directory of Open Access Journals (Sweden)

    Wang Zhao Lin

    2016-01-01

    Full Text Available The low wind-pressure conductor is a dedicated conductor which obtains low wind resistance coefficient by changing the sectional shape of the conductor and has extensive application prospect in electric power transmission lines in strong wind areas. Previous wind tunnel testing results showed that the wind resistance coefficient in unit length of the low wind-pressure aluminium conductor steel reinforced was obviously lower than that of the conventional aluminium conductor steel reinforced, and the control factors of manufacturing process of the low wind-pressure conductor were proposed. In this paper, the low wind-pressure aluminium conductor steel reinforced JLX1/G1A(DFY–680/45–338 was designed based on the structure optimization of the conventional aluminium conductor steel reinforced JL/G1A–630/45–45/7, and the service performance study of the conductor was carried out. Results showed that the mechanical properties, electrical properties and construction properties of the low wind-pressure conductor fully satisfied service requirements, and the conductor can be popularized and applied for transmission lines in strong wind areas.

  5. A Testing Platform for Validation of Overhead Conductor Aging Models and Understanding Thermal Limits

    Energy Technology Data Exchange (ETDEWEB)

    Irminger, Philip [ORNL; Starke, Michael R [ORNL; Dimitrovski, Aleksandar D [ORNL; Young II, Marcus Aaron [ORNL; Rizy, D Tom [ORNL; Stovall, John P [ORNL; Overholt, Philip N [U.S. Department of Energy, Office of Electricity Delivery and Energy Reliability (OE)

    2014-01-01

    Power system equipment manufacturers and researchers continue to experiment with novel overhead electric conductor designs that support better conductor performance and address congestion issues. To address the technology gap in testing these novel designs, Oak Ridge National Laboratory constructed the Powerline Conductor Accelerated Testing (PCAT) facility to evaluate the performance of novel overhead conductors in an accelerated fashion in a field environment. Additionally, PCAT has the capability to test advanced sensors and measurement methods for accessing overhead conductor performance and condition. Equipped with extensive measurement and monitoring devices, PCAT provides a platform to improve/validate conductor computer models and assess the performance of novel conductors. The PCAT facility and its testing capabilities are described in this paper.

  6. EEG generator--a model of potentials in a volume conductor.

    Science.gov (United States)

    Avitan, Lilach; Teicher, Mina; Abeles, Moshe

    2009-11-01

    EEG generator-a model of potentials in a volume conductor. The potential recorded over the cortex electro-corticogram (ECoG) or over the scalp [electroencephalograph (EEG)] derives from the activity of many sources known as "EEG generators." The recorded amplitude is basically a function of the unitary potential of a generator and the statistical relationship between different EEG generators in the recorded population. In this study, we first suggest a new definition of the EEG generator. We use the theory of potentials in a volume conductor and model the contribution of a single synapse activated to the surface potential. We then model the contribution of the generator to the surface potential. Once the generator and its contribution are well defined, we can quantitatively assess the degree of synchronization among generators. The measures obtained by the model for a real life scenario of a group of generators organized in a specific statistical way were consistent with the expected values that were reported experimentally. The study sheds new light on macroscopic modeling approaches which make use of mean soma membrane potential. We showed major contribution of activity of superficial apical synapses to the ECoG signal recorded relative to lower somatic or basal synapses activity.

  7. The brain, an orchestra without conductor

    CERN Document Server

    CERN. Geneva

    2008-01-01

    The brain is a highly distributed, self-organizing system that lacks central institutions for the coordination of cognitive and executive functions. This raises the question how the multiple parallel operations are bound together to give rise to coherent percepts, decisions and intentions. The hypothesis is proposed that time is used as coding space for the flexible definition of relations and the targeted routing of activity across highly interconnected networks.

  8. H/D isotope effects in high temperature proton conductors

    DEFF Research Database (Denmark)

    Bonanos, Nikolaos; Huijser, A.; Poulsen, Finn Willy

    2015-01-01

    The atomic mass ratio of ca. 2 between deuterium and hydrogen is the highest for any pair of stable isotopes and results in significant and measurable H/D isotope effects in high temperature proton conductors containing these species. This paper discusses H/D isotope effects manifested in O......-H/O-D vibration frequencies, the mobility of H+/D+ carriers, the kinetics of the electrochemical oxidation of H2/D2, the solubilities of H2O/D2O and, finally, the spontaneous electromotive force that appears across H2/D2 cells with proton conducting electrolytes. Comparable work on tritium-exchanged materials...... is also discussed. The results highlight the usefulness of isotope effects in the study of high temperature proton conductors....

  9. Critical area computation for real defects and arbitrary conductor shapes

    Institute of Scientific and Technical Information of China (English)

    Wang Jun-Ping; Hao Yue

    2006-01-01

    In current critical area models, it is generally assumed the defect outlines are circular and the conductors to be rectangle or the merger of rectangles. However, real defects and conductors associated with optimal layout design exhibit a great variety of shapes. Based on mathematical morphology, a new critical area model is presented, which can be used to estimate the critical area of short circuit, open circuit and pinhole. Based on the new model, the efficient validity check algorithms are explored to extract critical areas of short circuit, open circuit and pinhole from layouts.The results of experiment on an approximate layout of 4 × 4 shifts register show that the new model predicts the critical areas accurately. These results suggest that the proposed model and algorithm could provide new approaches for yield prediction.

  10. Structural Parameter Optimization of Multilayer Conductors in HTS Cable

    Institute of Scientific and Technical Information of China (English)

    Yan Mao; Jie Qiu; Xin-Ying Liu; Zhi-Xuan Wang; Shu-Hong Wang; Jian-Guo Zhu; You-Guang Guo; Zhi-Wei Lin; Jian-Xun Jin

    2008-01-01

    In this paper, the design optimization of the structural parameters of multilayer conductors in high temperature superconducting (HTS) cable is reviewed. Various optimization methods, such as the particle swarm optimization (PSO), the genetic algorithm (GA), and a robust optimization method based on design for six sigma (DFSS), have been applied to realize uniform current distribution among the multi- layer HTS conductors. The continuous and discrete variables, such as the winding angle, radius, and winding direction of each layer, are chosen as the design parameters. Under the constraints of the mechanical properties and critical current, PSO is proven to be a more powerful tool than GA for structural parameter optimization, and DFSS can not only achieve a uniform current distribution, but also improve significantly the reliability and robustness of the HTS cable quality.

  11. Mixed protonic and electronic conductors hybrid oxide synaptic transistors

    Science.gov (United States)

    Fu, Yang Ming; Zhu, Li Qiang; Wen, Juan; Xiao, Hui; Liu, Rui

    2017-05-01

    Mixed ionic and electronic conductor hybrid devices have attracted widespread attention in the field of brain-inspired neuromorphic systems. Here, mixed protonic and electronic conductor (MPEC) hybrid indium-tungsten-oxide (IWO) synaptic transistors gated by nanogranular phosphorosilicate glass (PSG) based electrolytes were obtained. Unique field-configurable proton self-modulation behaviors were observed on the MPEC hybrid transistor with extremely strong interfacial electric-double-layer effects. Temporally coupled synaptic plasticities were demonstrated on the MPEC hybrid IWO synaptic transistor, including depolarization/hyperpolarization, synaptic facilitation and depression, facilitation-stead/depression-stead behaviors, spiking rate dependent plasticity, and high-pass/low-pass synaptic filtering behaviors. MPEC hybrid synaptic transistors may find potential applications in neuron-inspired platforms.

  12. ADIDAS CONDUCTOR HI 配色美学

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    ADIDAS将于2010年春季推出以80年代香篮球鞋为设计灵感的CONDUCTOR HI,材质上不仅使用了皮革及魔皮想互衬托在配色上更是用出了神秘的黑色以及极富质感 的咖啡配色,质感不俗。

  13. Numerical Analysis of Conductor Galloping Limitation by Oscillation Frequency Detuning

    Directory of Open Access Journals (Sweden)

    I. I. Serguey

    2009-01-01

    Full Text Available A numerical method has been developed for calculation of conductor oscillations at the moment of galloping that takes account of pendulum  oscillation dampers in the form of eccentric loads. The method is recommended for a numerical analysis of various schemes pertaining to arrangement of horizontal pendulums in the span and their parameters including angles of their initial setting. The obtained results can be used for designing and operation of aerial power lines. 

  14. On Galateas - magnetic traps with plasma-embedded conductors

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, A I [Russian Research Centre ' Kurchatov Institute' , Moscow (Russian Federation); Savel' ev, V V [M.V. Keldysh Institute for Applied Mathematics, Russian Academy of Sciences, Moscow (Russian Federation)

    1998-11-30

    The introduction of plasma-embedded magnetically insulated current-carrying conductors into a plasma trap magnetic system radically increases the number of possible trap designs. The present review focuses on the studies of {beta} = 1 Galateas conducted in the 1990s. Both general and design-specific Galatea properties are discussed and for a number of specific schemes analytical and numerical calculations are performed. Experimental data on a number of electrical discharge Galateas are presented. (reviews of topical problems)

  15. What is a good conductor for metamaterials or plasmonics

    Science.gov (United States)

    Soukoulis, Costas M.; Koschny, Thomas; Tassin, Philippe; Shen, Nian-Hai; Dastmalchi, Babak

    2015-04-01

    We review conducting materials like metals, conducting oxides and graphene for nanophotonic applications. We emphasize that metamaterials and plasmonic systems benefit from different conducting materials. Resonant metamaterials need conductors with small resistivity, since dissipative loss in resonant metamaterials is proportional to the real part of the resistivity of the conducting medium it contains. For plasmonic systems, one must determine the propagation length at a desired level of confinement to estimate the dissipative loss.

  16. What is a good conductor for metamaterials or plasmonics

    Directory of Open Access Journals (Sweden)

    Soukoulis Costas M.

    2015-04-01

    Full Text Available We review conducting materials like metals, conducting oxides and graphene for nanophotonic applications. We emphasize that metamaterials and plasmonic systems benefit from different conducting materials. Resonant metamaterials need conductors with small resistivity, since dissipative loss in resonant metamaterials is proportional to the real part of the resistivity of the conducting medium it contains. For plasmonic systems, one must determine the propagation length at a desired level of confinement to estimate the dissipative loss.

  17. Stable Delay of Microstrip Line with Side Grounded Conductors

    Directory of Open Access Journals (Sweden)

    T. R. Gazizov

    2017-01-01

    Full Text Available Characteristics of transmission lines are addressed. Wave impedance and per-unit-length delay of the microstrip structure with grounded side conductors on three layers are calculated under different parameters of the structure. A line which provides the desired value of wave impedance and constant per-unit-length delay, at the expense of correction of the gaps on different layers, is proposed.

  18. Charge densities and charge noise in mesoscopic conductors

    Indian Academy of Sciences (India)

    M Büttiker

    2002-02-01

    We introduce a hierarchy of density of states to characterize the charge distribution in a mesoscopic conductor. At the bottom of this hierarchy are the partial density of states which represent the contribution to the local density of states if both the incident and the out-going scattering channel is prescribed. The partial density of states play a prominent role in measurements with a scanning tunneling microscope on multiprobe conductors in the presence of current flow. The partial density of states determine the degree of dephasing generated by a weakly coupled voltage probe. In addition the partial density of states determine the frequency-dependent response of mesoscopic conductors in the presence of slowly oscillating voltages applied to the contacts of the sample. The partial density of states permit the formulation of a Friedel sum rule which can be applied locally. We introduce the off-diagonal elements of the partial density of states matrix to describe charge fluctuation processes. This generalization leads to a local Wigner–Smith life-time matrix.

  19. Development of an aluminium stabilized reinforced superconducting conductor

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, D. [PTR Praezisionstechnik GmbH Maintal (Germany); Horvath, I.L. [Swiss Federal Inst. of Tech., Zuerich (Switzerland); Harzenmoser, M.; Neuenschwander, J. [Swiss Federal Labs. for Materials Testing and Research, Duebendorf (Switzerland); Wittgenstein, F. [CERN, Geneva (Switzerland)

    1996-07-01

    For high performance superconducting magnets as used in large detectors for the High Energy Physics or for magnets of magnetic storage devices (SMES) the mechanical stresses on the conductor go beyond the yield stress level of the high purity matrix stabilizer, specially if aluminium is used. Therefore, a novel method is proposed to join high strength aluminium strips to high purity aluminium stabilizer by using the electron beam (EB) welding. The proposed EB-welding, combined with roll-pressing under vacuum, provides the minimum heat input on the conductor in comparison with other welding techniques. This method provides the advantage to allow the production of very long conductor lengths and includes the potentiality of repairing without losing expensive material. As this process has to be adapted to the high purity aluminium on the one side and to the high strength material on the other, the authors started in a first step with investigation and development of the process, using standard laboratory machines together with laboratory-size tooling. In this report the development program is described and first results of the quality control measurements are presented.

  20. High-field thermal transports properties of REBCO coated conductors

    CERN Document Server

    Bonura, M

    2015-01-01

    The use of REBCO coated conductors is envisaged for many applications, extending from power cables to high-field magnets. Whatever the case, thermal properties of REBCO tapes play a key role for the stability of superconducting devices. In this work, we present the first study on the longitudinal thermal conductivity (k) of REBCO coated conductors in magnetic fields up to 19 T applied both parallelly and perpendicularly to the thermal-current direction. Copper-stabilized tapes from six industrial manufacturers have been investigated. We show that zero-field k of coated conductors can be calculated with an accuracy of ‡ 15% from the residual resistivity ratio of the stabilizer and the Cu/non-Cu ratio. Measurements performed at high fields have allowed us to evaluate the consistency of the procedures generally used for estimating in-field k in the framework of the Wiedemann-Franz law from an electrical characterization of the materials. In-field data are intended to provide primary ingredients for the ...

  1. The winding line for the CMS reinforced conductor

    CERN Document Server

    Fabbricatore, P; D'Urzo, C; Farinon, S; Gaddi, A; Levesy, B; Loche, L; Musenich, R; Rondeaux, F; Penco, R; Valle, N

    2002-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design field of the CMS superconducting magnet is 4 T, the length is 12.5 m and the free bore is 6 m. The use of a reinforced conductor for the CMS coil required a sustained activity of development at industrial level, to understand how to handle, to pre-bend and to wind the conductor with an inner winding technique. The winding line was designed and constructed according to this experience. The working principles of the line are under test through the winding of a prototype of a CMS coil module. The prototype has the same radius of a CMS module (6900 mm outer diameter), but a shorter axial length (670 mm against 2500 for the module). The critical operations are related to the accurate pre-bending of the conductor, the positioning of the turns into the winding, the axial compaction, and the correct handling of 50-ton windings. (9 refs).

  2. Nexans advances in all CSD route for REBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Bock, J.; Ehrenberg, J.; Hoppe, B.; Isfort, D.; Klein, M.; Rikel, M. [Nexans SuperConductors, Chemiepark Knapsack, Huerth (Germany)

    2007-07-01

    Development of REBCO coated conductors (CC) at Nexans SuperConductors (NSC) is focused on all chemical solution deposition (CSD) route that promises the best performance-to-price ratio in long lengths. The feasibility of all CSD approach is shown on the lab scale: using metalorganic deposition (MOD), NSC was able to produce YBCO/CeO{sub 2}/LZO/NiW CCs with J{sub c}(77 K,sf)=0.5 MA/cm{sup 2}. The major advance of NSC on a semi-industrial scale is the use of MOD route for production of high-quality La{sub 2}Zr{sub 2}O{sub 7} (LZO) coated NiW RABITS in lengths up to 12 m. With those substrates, it is possible to produce CCs with the simplest (one-buffer) architecture by depositing REBCO using other techniques (ISD at Theva, Ismaning; MOCVD at IOT, Braunschweig; HLPE at University of Cambridge, UK). The best short sample I{sub c}=280, 120 and 100 A/cm-width for HLPE, ISD, and MOCVD, respectively First long-length conductors show transport I{sub c}=40 A (10m-long, ISD). Further work is focused on optimisation of the already established mixed (MOD+PVD) approaches, understanding optimum architecture and processing conditions for the all-CSD route and developing tools for scaling those conditions to long-length production. (orig.)

  3. Stability measurements on the 50 kA SMES conductor

    Science.gov (United States)

    Pfotenhauer, M. J.

    Stability measurements have been made on a large aluminium stabilized conductor designed for use in a superconducting magnetic energy storage (SMES) coil. The conductor has been built to carry 50 kA at 1.8 K and in 4.6 T field. It consists of a 25.4 mm diameter, high purity aluminium stabilizer with eight superconducting strands of 2.8 mm diameter each, composed of 60% Cu, 40% NbTi. The strands are set in eight helical grooves, evenly spaced around the outer diameter of the aluminium. The conductor is designed for use in full scale SMES units and has been tested in the 1 m diameter, three-turn test coil of the University of Wisconsin proof of principle experiment (POPE). The POPE facility includes the test coil, a 4 T background magnet, a dewar for a 1.8 K, 1 atm environment and a 100 kA d.c. power supply. Test results demonstrate good agreement with a new dynamic stability model. The balance of time-dependent heat generation during current diffusion and time-dependent cooling to the helium produces three new features of stability: 1, a threshold current for propagation; 2, large propagation velocities; and 3, a finite length travelling normal zone. POPE measurements verify all three features of the dynamic stability model.

  4. Conductors for commercial MRI magnets beyond NbTi: requirements and challenges

    Science.gov (United States)

    Parizh, Michael; Lvovsky, Yuri; Sumption, Michael

    2017-01-01

    Magnetic resonance imaging (MRI), a powerful medical diagnostic tool, is the largest commercial application of superconductivity. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition and lifecycle cost including service. In this paper, we analyze conductor requirements for commercial MRI magnets beyond traditional NbTi conductors, while avoiding links to a particular magnet configuration or design decisions. Potential conductor candidates include MgB2, ReBCO and BSCCO options. The analysis shows that no MRI-ready non-NbTi conductor is commercially available at the moment. For some conductors, MRI specifications will be difficult to achieve in principle. For others, cost is a key barrier. In some cases, the prospects for developing an MRI-ready conductor are more favorable, but significant developments are still needed. The key needs include the development of, or significant improvements in: (a) conductors specifically designed for MRI applications, with form-fit-and-function readily integratable into the present MRI magnet technology with minimum modifications. Preferably, similar conductors should be available from multiple vendors; (b) conductors with improved quench characteristics, i.e. the ability to carry significant current without damage while in the resistive state; (c) insulation which is compatible with manufacturing and refrigeration technologies; (d) dramatic increases in production and long-length quality control, including large-volume conductor manufacturing technology. In-situ MgB2 is, perhaps, the closest to meeting commercial and technical requirements to become suitable for commercial MRI. Conductor technology is an important, but not the only, issue in introduction of HTS/MgB2 conductor into commercial MRI magnets. These

  5. Exploring the limits of a very large Nb{sub 3}Sn conductor: the 80 kA conductor of the ITER toroidal field model coil

    Energy Technology Data Exchange (ETDEWEB)

    Duchateau, J.L.; Ciazynski, D.; Guerber, O.; Park, S.H.; Zani, L. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Fietz, W.H.; Ulbricht, A.; Zahn, G. [Association Euratom-FZK Forschungszentrum, Karlsruhe (Germany)

    2003-07-01

    In Phase II experiment of the International Thermonuclear Experimental Reactor (ITER) Toroidal Field Model Coil (TFMC) the operation limits of its 80 kA Nb{sub 3}Sn conductor were explored. To increase the magnetic field on the conductor, the TFMC was tested in presence of another large coil: the EURATOM-LCT coil. Under these conditions the maximum field reached on the conductor, was around 10 tesla. This exploration has been performed at constant current, by progressively increasing the coil temperature and monitoring the coil voltage drop in the current sharing regime. Such an operation was made possible thanks to the very high stability of the conductor. The aim of these tests was to compare the critical properties of the conductor with expectations and assess the ITER TF conductor design. These expectations are based on the documented critical field and temperature dependent properties of the 720 superconducting strands which compose the conductor. In addition the conductor properties are highly dependent on the strain, due to the compression appearing on Nb{sub 3}Sn during the heat treatment of the pancakes and related to the differential thermal compression between Nb{sub 3}Sn and the stainless steel jacket. No precise model exists to predict this strain, which is therefore the main information, which is expected from these tests. The method to deduce this strain from the different tests is presented, including a thermalhydraulic analysis to identify the temperature of the critical point and a careful estimation of the field map across the conductor. The measured strain has been estimated in the range -0.75% to -0.79 %. This information will be taken into account for ITER design and some adjustment of the ITER conductor design is under examination. (authors)

  6. Nanocrystalline Axially Bridged Iron Phthalocyanine Polymeric Conductor: (μ-Thiocyanato(phthalocyaninatoiron(III

    Directory of Open Access Journals (Sweden)

    Eiza Shimizu

    2016-01-01

    Full Text Available Skewered Iron(III phthalocyanine conducting polymer can be constructed with the utilization of axial thiocyanato ligands ((μ-thiocyanato(phthalocyaninatoiron(III; (FeIII(Pc(SCNn thereby creating additional avenues for electron transport through a linear SCN bridge, apart from the intermolecular π-π orbital overlap between the Pc molecules. In this paper, we report on the conversion of bulk FeIII(Pc(SCNn polymeric organic conductor into crystalline nanostructures through horizontal vapor phase growth process. The needle-like nanostructures are deemed to provide more ordered and, thus, more π-π interactive interskewer FeIII(Pc(SCNn polymer orientation, resulting in a twofold increase of its electrical conductivity per materials density unit.

  7. A Boundary Element Solution to the Problem of Interacting AC Fields in Parallel Conductors

    Directory of Open Access Journals (Sweden)

    Einar M. Rønquist

    1984-04-01

    Full Text Available The ac fields in electrically insulated conductors will interact through the surrounding electromagnetic fields. The pertinent field equations reduce to the Helmholtz equation inside each conductor (interior problem, and to the Laplace equation outside the conductors (exterior problem. These equations are transformed to integral equations, with the magnetic vector potential and its normal derivative on the boundaries as unknowns. The integral equations are then approximated by sets of algebraic equations. The interior problem involves only unknowns on the boundary of each conductor, while the exterior problem couples unknowns from several conductors. The interior and the exterior problem are coupled through the field continuity conditions. The full set of equations is solved by standard Gaussian elimination. We also show how the total current and the dissipated power within each conductor can be expressed as boundary integrals. Finally, computational results for a sample problem are compared with a finite difference solution.

  8. Conductor and joint test results of JT-60SA CS and EF coils using the NIFS test facility

    Science.gov (United States)

    Obana, Tetsuhiro; Takahata, Kazuya; Hamaguchi, Shinji; Kizu, Kaname; Murakami, Haruyuki; Chikaraishi, Hirotaka; Noguchi, Hiroki; Kobuchi, Takashi; Moriuchi, Sadatomo; Imagawa, Shinsaku; Mito, Toshiyuki; Tsuchiya, Katsuhiko; Natsume, Kyohei; Yoshida, Kiyoshi; Nomoto, Kazuhiro; Kim, Tae-hyun

    2016-01-01

    In 2007, JAEA and NIFS launched the test project to evaluate the performance of cable-in-conduit (CIC) conductors and conductor joints for the JT-60SA CS and EF coils. In this project, conductor tests for four types of coil conductor and joint tests for seven types of conductor joint have been conducted for the past eight years using the NIFS test facility. As a result, the test project indicated that the CIC conductors and conductor joints fulfill the design requirement for the CS and EF coils. In addition, the NIFS test facility is expected to be utilized as the test facility for the development of a conductor and conductor joint for the purpose of the DEMO nuclear fusion power plant, provided that the required magnetic field strength is within 9 T.

  9. Loss and Inductance Investigations in a 4-layer Superconducting Prototype Cable Conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa;

    1999-01-01

    One important issue in the design and optimization of a superconducting cable conductor is the control of the current distribution between single tapes and layers. This presentation is based on a number of experiments performed on a 4-layer three meter long prototype superconducting cable conductor......-losses are measured as a function of transport current and a given current distribution and compared with the monoblock model. Recommendations for design of future cable conductor prototypes are given....

  10. Scattering by a perfect electromagnetic conductor (PEMC) plate embedded in lossy medium

    Science.gov (United States)

    Ahmed, Saeed; Khalid Khan, Muhammad; Rehman, Atta Ur

    2016-07-01

    In this article, we develop an analytic theory for a perfect electromagnetic conductor (PEMC) plate embedded in lossy medium. The duality transformation introduced by Lindell and Sihvola is applied to study the electromagnetic wave scattering by a PEMC plate. Perfect electric conductor and perfect magnetic conductor are the limiting cases of PEMC media. Here, we study monoscattering by PEMC plate embedded in four different soil models. Numerical results are discussed and compared with the available literature.

  11. A comparison of graphene, superconductors and metals as conductors for metamaterials and plasmonics

    OpenAIRE

    Tassin, Philippe; Koschny, Thomas; Kafesaki, Maria; Soukoulis, Costas M.

    2012-01-01

    Recent advancements in metamaterials and plasmonics have promised a number of exciting applications, in particular at terahertz and optical frequencies. Unfortunately, the noble metals used in these photonic structures are not particularly good conductors at high frequencies, resulting in significant dissipative loss. Here, we address the question of what is a good conductor for metamaterials and plasmonics. For resonant metamaterials, we develop a figure-of-merit for conductors that allows f...

  12. Critical Current in YBCO Coated Conductors in the Presence of a Macroscopic Defect (POSTPRINT)

    Science.gov (United States)

    2010-03-01

    AFRL-RZ-WP-TP-2010-2084 CRITICAL CURRENT IN YBCO COATED CONDUCTORS IN THE PRESENCE OF A MACROSCOPIC DEFECT (POSTPRINT) Milan Polak and...CRITICAL CURRENT IN YBCO COATED CONDUCTORS IN THE PRESENCE OF A MACROSCOPIC DEFECT (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c...display, or disclose the work. 14. ABSTRACT We have studied the effects of localized defects in the YBCO coated conductors on the critical current. The

  13. 厚膜金导体浆料%Thick-Film Gold Conductor Pastes

    Institute of Scientific and Technical Information of China (English)

    李世鸿

    2001-01-01

    概括介绍了厚膜金导体浆料。通过改变金粉、粘结剂和有机载体等主要组份的类型和含量,可以制得多种金浆料。①粘结剂类型对厚膜金导体的性能有较大的影响。根据附着机理分类,厚膜金导体分为4种主要类型,即玻璃结合型、反应结合型、混合结合型和表面活化结合型。②金粉颗粒的均匀性、单分散性、表面形态及尺寸对浆料的印刷性能和烧结性能影响大。颗粒表面越光滑,对提高印刷性能越有利。光滑的表面吸附有机载体较少,可减少导体膜在烘干—烧结时的收缩率。③有机载体的含量和流变学性能影响金浆料的印刷性能及烘干—烧结时的收缩率。④金浆中添加起合金化作用的元素,可提高导体在铝丝键合体系及Pb-In焊接体系的热老化性能。⑤为适应新的厚膜工艺技术的需要,研制可光刻的厚膜金导体浆料和金的金属有机浆料[Au MOC]。%Thick-film gold conductor pastes are summarized in this paper.Many kinds of gold pastes are made by changing types and contents of main components such as gold powder,binder and organic vehicle.1.The types of binders deeply affect the characteristics of thick-film gold conductors.Depending on the adhesion mechanisms,thick-film gold conductors are classified into four main types:the fritted-bonded,the reactivity-bonded,the mixed-bonded and the surface activated-bonded systems.2.The homogeneity,monodisperesability,morphology and size of the gold powder particles greatly influence the paste printability and sintering properties.The smoother surface renders the pastes greater printability,and the lower vehicle absorption rate resulting from smooth surface can reduce shrinkage.3.The content and rheology of organic vehicle influence the paste printability and dried-fired shinkage.4.The addition of alloyed elements to gold pastes can improve the thermal-ageing performance in Al-wire bonding and

  14. 特殊导线的应用比较%Application Comparison of Special Conductor

    Institute of Scientific and Technical Information of China (English)

    姚洪林

    2012-01-01

    This article compares 500mm2 Section of ACCC,Gap type conductor and plain conductor suppose increase the capacity of the conductors. And Chose the suitable type of conductor based on the comparison.%本文假设导线达到倍容目的,针对截面是500mm2碳纤维导线、间隙型导线、普通导线进行比较,确定特殊导线的选择.

  15. Study on galloping behavior of iced eight bundle conductor transmission lines

    Science.gov (United States)

    Zhou, Linshu; Yan, Bo; Zhang, Liang; Zhou, Song

    2016-02-01

    Wind tunnel test was carried out to obtain the aerodynamic coefficients of an eight bundle conductor accreted with crescent-shaped ice. A user-defined cable element with torsional degree of freedom is developed in ABAQUS software to capture the torsional deformation of the iced conductors during galloping. By means of the user-defined cable element, different damping ratios in in-plane, out-of-plane and torsional directions of the conductors can be defined and the aerodynamic forces varying with their motion status can be exerted on the conductors conveniently when ABAQUS is used to simulate galloping of transmission lines. A wind tunnel test to model galloping of an iced eight bundle conductor segment was carried out, and the validity of the numerical simulation method is demonstrated by the agreement of the galloping orbit of the bundle conductor segment model recorded in the test and that by the numerical simulation. Furthermore, galloping behavior, including dynamic responses, galloping orbits, frequencies, vibration modes and amplitudes, of typical iced eight bundle conductor transmission lines in the cases of different span lengths, initial tensions in sub-conductors, wind velocities, angles of wind attack and damping ratios is studied, and the galloping behavior of the lines with internal resonance conditions is discussed. The obtained results may provide a fundamental tool for the development of anti-galloping techniques of eight bundle conductor transmission lines.

  16. Calculation of the surface effect in the ferromagnetic conductor with the harmonic electromagnetic field

    Science.gov (United States)

    Nosov, G. V.; Kuleshova, E. O.; Vassilyeva, Yu Z.; Elizarov, A. I.

    2016-04-01

    The authors of the paper have obtained formulas for analytical calculation of the constants with the harmonic electromagnetic field, which characterize the surface layer (a skin layer) of the ferromagnetic conductors in case of heating and nonlinear magnetic properties, which can be used for practical calculation of the electromagnetic screens, rotors of the electrical machines and inductive heating installations. A nonlinear dependence of the magnetic induction on the magnetic tension of the ferromagnetic conductor is replaced by one or two linear sections. It is considered that the skin layer of the conductor has constant quantities of the specific conductivity and averaged temperature. Linear electrodynamics equations are solved for the conductive half-space. Parameters of the ferromagnetic conductor's surface layer are calculated: magnetic permeability, the thickness of the skin layer and its averaged temperature, exposure time of the electromagnetic field on the conductor with the established maximum temperature on the conductor's surface, pressure of the field on the conductor and its resistance, inductivity of the internal magnetic field in the conductor, the thermal energy capacity. The methods credibility is confirmed with the concurrence of the resistance and inductiviry of the ferromagnetic conductor with analogous quantities from other methods.

  17. Keeping an eye on the conductor: neural correlates of visuo-motor synchronization and musical experience.

    Science.gov (United States)

    Ono, Kentaro; Nakamura, Akinori; Maess, Burkhard

    2015-01-01

    For orchestra musicians, synchronized playing under a conductor's direction is necessary to achieve optimal performance. Previous studies using simple auditory/visual stimuli have reported cortico-subcortical networks underlying synchronization and that training improves the accuracy of synchronization. However, it is unclear whether people who played regularly under a conductor and non-musicians activate the same networks when synchronizing with a conductor's gestures. We conducted a functional magnetic resonance imaging (fMRI) experiment testing nonmusicians and musicians who regularly play music under a conductor. Participants were required to tap the rhythm they perceived from silent movies displaying either conductor's gestures or a swinging metronome. Musicians performed tapping under a conductor with more precision than nonmusicians. Results from fMRI measurement showed greater activity in the anterior part of the left superior frontal gyrus (SFG) in musicians with more frequent practice under a conductor. Conversely, tapping with the metronome did not show any difference between musicians and nonmusicians, indicating that the expertize effect in tapping under the conductor does not result in a general increase in tapping performance for musicians. These results suggest that orchestra musicians have developed an advanced ability to predict conductor's next action from the gestures.

  18. Study on local inhomogeneity in TFA-MOD YBCO coated conductor by use of low temperature scanning laser microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, M. [Department of EESE, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan)]. E-mail: inoue@ees.kyushu-u.ac.jp; Kiss, T. [Department of EESE, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan); Tokutomi, H. [Department of EESE, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan); Shoyama, T. [Department of EESE, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan); Imamura, K. [Department of EESE, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan); Takeo, M. [Department of EESE, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan); Iijima, Y. [Fujikura Ltd., Tokyo 135-8512 (Japan); Kakimoto, K. [Fujikura Ltd., Tokyo 135-8512 (Japan); Saitoh, T. [Fujikura Ltd., Tokyo 135-8512 (Japan); Tokunaga, Y. [Superconductivity Research Laboratory, Tokyo 130-0062 (Japan); Izumi, T. [Superconductivity Research Laboratory, Tokyo 130-0062 (Japan); Shiohara, Y. [Superconductivity Research Laboratory, Tokyo 130-0062 (Japan)

    2005-10-01

    We investigated the local inhomogeneity of flux flow dissipation by use of low temperature scanning laser microscopy (LTSLM) in a Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) coated conductor obtained by the Metal-Organic Deposition process using metal trifuluoroacetate (TFA-MOD process). The LTSLM images showed that the highest J {sub c} value in local region reached almost two times higher than the minimum value, while the global J {sub c} was limited by the weakest spot. Typical length scale of the spatial inhomogeneity of J {sub c} was about several tens to hundreds {mu}m.

  19. With or without a conductor: Comparative analysis of leadership models in the musical ensemble

    Directory of Open Access Journals (Sweden)

    Kovačević Mia

    2016-01-01

    Full Text Available In search of innovative models of work organization and therefore the artistic process of one musical ensemble, in the last ten years musical ensembles have developed examples of non-traditional artistic-performing decisions and organizational practice. The paper is conceived as a research and analysis of the dominant models of leadership (i.e. organizing, conducting business applicable on the music ensembles and experiences of the musicians. The aim is to recognize and define leadership styles that encourage the increase of motivation and productivity of musicians within the musical ensemble. The paper will specifically investigate the relationship and differences between the two dominant models of leadership, leadership of conductor and collaborative leadership. At the same time, the paper describes and analyses an experiment that was conducted by the Ensemble Metamorphosis, which applied into their work two dominant models of leadership. In an effort to increase the motivation and productivity of musicians, Ensemble Metamorphosis also searched for a new management model of work organization and a new model of leadership. The aim of this paper was therefore to investigate the effects of leadership models that improve the artistic quality, motivation of the musicians, psychological climate and overall increase productivity of musical organization.

  20. Improving Students' Conceptual Understanding of Conductors and Insulators

    CERN Document Server

    Bilak, Joshua

    2016-01-01

    We examine the difficulties that introductory physics students, undergraduate physics majors, and physics graduate students have with concepts related to conductors and insulators covered in introductory physics by giving written tests and interviewing a subset of students. We find that even graduate students have serious difficulties with these concepts. We develop tutorials related to these topics and evaluate their effectiveness by comparing the performance on written pre-/post-tests and interviews of students who received traditional instruction vs. those who learned using tutorials.