[PDF] Low Frequency Charge Density Wave Dynamics eBook

Author : Arley Cleveland Marley
Publisher :
Page : 400 pages
File Size : 11,23 MB
Release : 1995
Category :
ISBN :

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The low frequency dynamics of the charge-density waves in NbSe$sb3$ and TaS$sb3$ were investigated using low frequency conductance fluctuations. Simultaneous measurements of the fluctuations in the voltage and the differential resistance revealed a theory of threshold voltage fluctuations can only partially describe some of the fluctuations in the I-V curve. Noise measurements performed with an ac drive current characterized the fluctuations and showed that other parameters, in addition to the threshold, must be fluctuating to fully account for the fluctuations. In mesoscopic samples, the observation of discrete switching in the voltage allowed estimates of the dynamical coherence length ranging from $rm{approx}100mu m$ up to the entire sample length of $rm{approx}1000mu m.$ Experiments to determine if the low frequency dynamics are equilibrium or nonequilibrium processes showed that the dynamics involve a combination of equilibrium and nonequilibrium dynamics. The equilibrium dynamics can be described by a rough free energy landscape with extreme sensitivity of the local details of the landscape to changes in the temperature or current. The nonequilibrium dynamics were directly related to the drive current.

Author : L.P. Gor'kov
Publisher : Elsevier
Page : 495 pages
File Size : 43,23 MB
Release : 2012-12-02
Category : Science
ISBN : 0444600736

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The latest addition to this series covers a field which is commonly referred to as charge density wave dynamics. The most thoroughly investigated materials are inorganic linear chain compounds with highly anisotropic electronic properties. The volume opens with an examination of their structural properties and the essential features which allow charge density waves to develop. The behaviour of the charge density waves, where interesting phenomena are observed, is treated both from a theoretical and an experimental standpoint. The role of impurities in statics and dynamics is considered and an examination of the possible role of solitons in incommensurate charge density wave systems is given. A number of ways to describe charge density waves theoretically, using computer simulations as well as microscopical models, are presented by a truely international board of authors.

Author : Gyula Hutiray
Publisher : Springer
Page : 564 pages
File Size : 38,71 MB
Release : 1985
Category : Science
ISBN :

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Neutron and x-ray scattering study on K0.3MoO3 and other quasi one dimensional conductors -- X-ray study of charge-density wave in K0.30Mo03 under electric fields -- Transmission electron microscopy for imaging and diffraction studies of low dimensional transition metal chalcogenides -- Aspects of charge-density waves in the TaTe4-NbTe4 structures and in 2H-TaSe2 -- Charge density waves, phasing, sliding and related phenomena in NbSe3 and other transition metal chalcogenides -- Structural and electrical properties interpretation through band structure calculations on the (MSe4)nI SERIES (M = Nb, Ta). -- Defects and charge density waves in irradiated layer and chain compounds -- Electron diffraction charge density wave studies in the chalcogenide compounds (MX4)nI -- Neutron studies of the blue bronzes K0.3MoO3 and Rb0.3MoO3 -- The effect of a magnetic field on the discotm1ensurate to commensurate transition in 2H TaSe2 -- High pressure investigation of the cdw phase diagram of 1T-TaS2 -- Landau theory of 2H-TaSe2 -- Multidomain structures of incommensurate phases in CDW states of 2H-TaSe2 -- Electron microscopy of charge density wave defects in 1T-TaS2 and 1T-TaSe2 -- Aspects of strong electron-phonon coupling related to the CDW transition at temperatures above it -- Elastic and other properties at the commensurate-incommensurate transition in 2H-TaSe2 -- CDW phase mode investigation in the FIR in K0.3MaO3 and band structure calculation -- 93Nb NMR study of CDW in (NbSe4)10/3I single crystal -- Electronic Properties and Fe57 Mössbauer measurements of T1+xNb3-xSe10 with T = Fe, Cr -- Transport and Mössbauer studies of the peierls transition in Fe-doped K0.30MoO3 -- Charge density wave instabilities in quasi two-dimensional oxides n-Mo4O11 and ?-Mo4O11 -- Thermal conductivity of layered dichalcogenides -- Tunneling study of commensurate charge density wave states in 1T-TaS2 -- Galvanomagnetic properties of the quasi-two dimensional purple bronze K0.9Mo6O17 -- Non-local elastic forces in charge-density wave systems -- Soliton model of charge-density-wave depinning -- Dynamics of incommensurate structures -- Some problems arising from electrostatic potential in CDW behavior -- The single domain model of charge-density wave transport -- On the microscopic theory of kinetic phenomena in peierls conductors -- Near commensurability effects on charge density wave dynamics -- Shift in the longitudinal sound velocity due to sliding charge density waves -- Microscopic local mechanisms for "Noises" generated by moving CDW -- Phase vortices and CDW conduction noise -- Damping of CDW-condensate motion by interaction with thermal phasons -- Microscopic theory of interaction of CDW with impurities -- Quantum effects in the Josephson approach to a CDW -- Fokker planck theory of the classical charge density wave model with current noise -- Travelling charge density waves : A mean field treatment -- Coherent and incoherent effects in charge density wave transport -- Threshold field, electrical conductivity and time-dependent voltage in transition metal tri- and tetrachalcogenides -- Solitons in TaS3 experiment -- Thermal gradient experiments on the charge-density-wave conduction noise spectrum -- Broadband noise in orthorhombic TaS3 -- High field I-V characteristics of orthorhombic TaS3 -- Inertial dynamics of CDW transport in NbSe3 -- Frequency dependent conductivity of CDW compounds -- AC conductivity of the blue bronze K0.3 MoO3 -- Subharmonic shapiro steps, devil's staircase, and synchronization in RF-driven CDW conductors -- Mode locking and chaos in sliding charge-density-wave systems -- Chaos in charge density wave systems -- Contribution of CDW motion to the hall effect and to the transverse conductivity in TaS3. experiment -- Contribution of CDW motion to the hall effect and to the transverse conductivity. Theory -- Dependence of the elastic modulus of TaS3 on the CDW current -- Low frequency elastic properties of materials containing a sliding CDW -- The conductivity of orthorhombic TaS3 under uniaxial strain -- Ohmic and nonlinear transport of (TaSe4)2I under pressure -- Pinning, metastability and sliding of charge-density-waves -- Distortion, metastability and breaking in charge-density wave transport: Recent experiments on niobium triselenide, suggesting a new mean-field approach -- Bistable configurations of the pinned charge density wave: Random-field-model dynamics observed in rearrangement prior to depinning -- Electric field induced relaxation of metastable states in TaS3 -- Remanent deformation of CDWs -- Relaxation of the deformed cdw state: electric and thermal hysteresis -- Thermal hysteresis in the thermopower of o-TaS3 -- Delayed switching between normal and CDW conducting states in o-TaS3 -- The effect of uniaxial strain on metastable states in TaS3 -- Influence of defects on the metastable states of o-TaS3 -- Charge density wave transport in the blue bronzes K0.30MoO3 and Rb0.30MoO3 : metastability, hysteresis and memory effects -- Effects of irradiation on the blue bronzes K0.30MoO3 and Rb0.30MoO3 -- Relaxation of metastable states in blue bronze K0.3MoO3 -- Incommensurate ferroelectrics -- Commensurate and incommensurate phases of a two-dimensional lattice of superconducting vortices -- (TMTSF)2X compounds: Superconductivity, spin-density waves and anion ordering -- Impurity pinning in quasi-1D superconductivity -- Numerical studies of the effect of a wall on SDW in a jellium -- Pinning of amplitude solitons in Peierls systems with impurities -- New resistive state in low dimensional superconductor TaSe3 -- Switching in cdw systems and in V02 -- A comparative study -- The effect of varying the bandfilling in a Peierls conductor -- Solitons and polarons in a spin density wave chain -- Charge density waves in superionic conductors -- Numerical study of impurity pinning in one-dimensional interacting electron systems -- Multivalued charge-density waves.

Author : Katarina Cicak
Publisher :
Page : 0 pages
File Size : 22,53 MB
Release : 2020
Category :
ISBN :

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We investigated low-temperature dynamics in a charge density wave (CDW) conductor NbSe3, a widely studied representative of a class of systems of driven periodic media with quenched disorder and relevant to a wider group of systems exhibiting collective transport behaviors. To date, theoretical efforts have not converged to produce a consistent description of the rich dynamics observed in these systems, especially in the low temperature regime. We developed modern sample preparation techniques and used frequency- and time-domain transport measurements below the second characteristic Peierls CDW transition to investigate the regime of temporally-ordered collective creep in NbSe3 samples in the low temperature regime between 15 K and 32 K. By measuring the frequency of coherent oscillations between two characteristic electric field thresholds, ET and ET*, we show that in nine high-quality samples, pure, Ta-, or Ti-doped, the current-field relation for the collective transport in this regime closely follows a modified Anderson-Kim form across five orders of magnitude with thermally- and field-activated behavior above ET for a range of temperatures. This study, combined with our transport relaxation measurements, provides relevant length, energy, and time scales that set the dynamics in this regime and reveals that the collective dynamics, governed by large length and energy scales, must be reconciled with microscopic local dynamics, with barriers at orders of magnitude smaller scales. The interplay between the collective and local mechanisms set the dynamics that is responsible for extremely slow (creep-like) collective, yet temporally-ordered behavior. Combined with the existing work, our results paint a consistent picture of a transport phase diagram for charge-density waves, and density-wave systems in general, and provide essential ingredients for a much-needed correct theoretical description of these systems.

Author : D. Jerome
Publisher : Springer Science & Business Media
Page : 524 pages
File Size : 38,89 MB
Release : 2013-12-14
Category : Technology & Engineering
ISBN : 1489936114

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Research activities in low dimensional conductors have shown a rapid growth since 1972 and have led to the discovery of new and remarkable phy sical properties unique to both molecular and inorganic conductors exhibi ting one-dimensional transport behaviour. This NATO Institute was a conti nuation of aseries of NATO Advanced Study Institutes of Worshops which took place at regular intervals till 1979. This is the first time, however, that charge density wave transport and electronic properties of low dimen sional organic conductors are treated on an equal footing. The program of the Institute was framed by tutorial lectures in the theories and experiments of low dimensional conductors. The bulk of the course covered two series of low-dimensional mate rials with their respective properties. 1) The I-D inorganic conductors exhibiting the phenomena of sliding charge density waves, narrow band noise, memory effects, etc ..• 2) Low-dimensional crystallized organic conductors giving rise to various possibilities of ground states, spin-Peierls, spin density wave, Peierls, superconductivity and magnetic-field induced spin density wave, etc ... Since it has been established from the beginning that this Institute was to be devoted essentially to the Physics of Low Dimensional Conductors, only one main course summarized the progress in chemistry and material preparation.

Author : George Gruner
Publisher : CRC Press
Page : 288 pages
File Size : 23,91 MB
Release : 2018-03-08
Category : Science
ISBN : 0429969562

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?Density Waves in Solids is written for graduate students and scientists interested in solid-state sciences. It discusses the theoretical and experimental state of affairs of two novel types of broken symmetry ground states of metals, charge, and spin density waves. These states arise as the consequence of electron-phonon and electron-electron interactions in low-dimensional metals.Some fundamental aspects of the one-dimensional electron gas, and of the materials with anisotropic properties, are discussed first. This is followed by the mean field theory of the phases transitions?discussed using second quantized formalism?together with the various experimental observations on the transition and on the ground states. Fluctuation effects and the collective excitations are reviewed next, using the Ginzburg-Landau formalism, followed by the review of the interaction of these states with the underlying lattice and with impurities. The final chapters are devoted to the response of the ground states to external perturbations.