Author
A. Meerschaut
Bio: A. Meerschaut is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Charge density & Niobium. The author has an hindex of 4, co-authored 5 publications receiving 477 citations.
Papers
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TL;DR: In this paper, the suppression by electric fields of longitudinal resistivity anomalies at 145 and 59 K in the compound Nb${\mathrm{Se}}_{3} was reported, and attributed the observed suppression to Zener breakdown across extremely small gaps introduced by the presence of charge density waves.
Abstract: We report the suppression by electric fields of longitudinal resistivity anomalies at 145 and 59 K in the compound Nb${\mathrm{Se}}_{3}$. Sample resistance was determined by conventional four-probe dc measurement as well as with short current pulses. We attribute the observed suppression to Zener breakdown across extremely small gaps introduced by the presence of charge density waves.
342 citations
TL;DR: The crystal structure of NbSe3 has been refined from single crystal X-ray diffraction data as discussed by the authors, which shows that the 145K transition in the electrical resistivity is not accompanied by a structural distortion.
Abstract: The crystal structure of NbSe3 has been refined from single crystal X-ray diffraction data. It has a monoclinic symmetry with lattice parameters: a=10.009 AA, b=3.4805 AA, c=15.629 AA, beta =109.47 AA, space group P21/m and six formulae per unit cell. The crystal structure of NbSe3 as determined at 100K shows that the 145K transition in the electrical resistivity is not accompanied by a structural distortion. Except for the decrease due to thermal contraction all interatomic distances are found to be the same. This is compatible with the proposed model of the charge-density-waves formation which has been put forward in order to explain the physical properties of the 145K transition. Electron diffraction pictures taken above and below the transition give direct evidence of the charge-density-waves formation at the transition. At 120K in agreement with Tsutsumi et al. (1977) the pictures contain superstructure spots at the (h,k+or-0.243, l) positions. Contrary to what has been reported by the same authors, the authors have found that at 3K above the transition the electron diffraction pictures do not contain the diffuse scattering streaks corresponding to the planes at k'=k+or-0.243, which would indicate fluctuations of the CDW above the transition.
118 citations
TL;DR: In this article, electron microscopy study permits them to show clearly and characterise the charge density waves which appear at 263 and 285K in (TaSe4)2I and (NbSe4103/I) respectively.
Abstract: The new tetrachalcogenide compounds have a one-dimensional structure and two of these show transport properties which are characteristic of this type of conductor. The authors electron microscopy study permits them to show clearly and characterise the charge density waves which appear at 263 and 285K in (TaSe4)2I and (NbSe4)103/I respectively. Moreover, they describe the behaviour of (TaSe4)3I and (NbSe4)3I when the temperature changes. These compounds undergo a space group change around 200 and 280K respectively. The results are connected to those obtained in other works by the study of transport phenomena or by band scheme calculations.
38 citations
TL;DR: In this article, electrical conductivity measurements on these compounds together with a comparison of the two-dimensional compounds NbSe2 and TaSe2 were presented, together with the comparison of their electrical conductivities.
Abstract: By direct reaction between selenium and tantalum or niobium in stoichiometric proportions one gets TaSe31 or NbSeB a fibrous material, the structure of which can be described as “unidimensional”. We present, hereafter, electrical conductivity measure-ments on these compounds together with a comparison of the “two dimensional” compounds NbSe2 and TaSe2.
4 citations
TL;DR: The triselenide of niobium was recently prepared and described by A. Meerschaut and J. Rouxel as discussed by the authors, and the structure was determined from a collection of intensities by an automatic diffractometer Nonius Cad 3.
Abstract: The triselenide of niobium was recently prepared and described by A. Meerschaut and J . Rouxel.' NbSe3 is a monoclinic system. The structure was determined from a collection of intensities by an automatic diffractometer Nonius Cad 3. The reliability factor was refined to a minimum value of 0.046 when an anisotropic temperature factor for all the atoms was considered. The atoms are all in position 2e with spacegroup P2'/m.
1 citations
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TL;DR: In many materials with a highly anisotropic band structure, electron-phonon interactions lead to a novel type of ground state called the charge-density wave as mentioned in this paper, which can, even for small electric fields, carry current in a fashion originally envisioned by Frohlich.
Abstract: In many materials with a highly anisotropic band structure, electron-phonon interactions lead to a novel type of ground state called the charge-density wave. The condensate is pinned to the underlying lattice by impurities and by boundary effects, but can, even for small electric fields, carry current in a fashion originally envisioned by Fr\"ohlich. This review discusses some of the underlying theories and the main experimental observations on this new collective transport phenomenon. The frequency- and electric-field-dependent conductivity, current oscillations, electric-field-dependent transport coefficients and elastic properties, together with nuclear-magnetic-resonance experiments, provide clear evidence for a translational motion of the condensate. Various theories, involving classical and quantum-mechanical concepts, are able to account for a broad variety of experimental findings, which were also made in the presence of combined dc and ac fields.
1,308 citations
TL;DR: In this article, the authors survey recent theories on the transition between commensurate (C) and incommensurate phases, and on properties of the I phase, and the devil's staircase concept for the I phases is described.
Abstract: Surveys recent theories on the transition between commensurate (C) and incommensurate (I) phases, and on properties of the I phase. The devil's staircase concept for the I phase is described. Differences between theories in two and three dimensions are discussed, together with those on chaotic structures.
1,042 citations
TL;DR: In this article, the authors present the most salient developments of research on organic conductors and superconductors during the past 10 years, including lattice instability in TTF-TCNQ and related compounds, superconducting or antiferromagnetic instabilities in the (TMTSF) 2 X series.
Abstract: This review attempts to present the most salient developments of research on organic conductors and superconductors during the past 10 years. A theoretical introduction treats instabilities of quasi-one-dimensional electron systems and associated precursor effects which are relevant to the experimental results on organic conductors. We then describe the characterization of quasi-one-dimensional organic conductors by their transport, optical and magnetic properties. Finally, two sections are devoted to the experimental investigation of the low temperature instabilities: lattice instability in TTF-TCNQ and related compounds, superconducting or antiferromagnetic instabilities in the (TMTSF) 2 X series. The importance of one-dimensional fluctuations is emphasized in both lattice and superconducting instabilities.
804 citations
TL;DR: In this paper, the static and dynamic properties of spontaneous superstructures formed by electrons are reviewed, and a special attention is paid to the collective effects in pinning and sliding of these structures, and the glassy properties at low temperature.
Abstract: This article reviews the static and dynamic properties of spontaneous superstructures formed by electrons. Representations of such electronic crystals are charge density waves (CDW) and spin density waves in inorganic as well as organic low-dimensional materials. A special attention is paid to the collective effects in pinning and sliding of these superstructures, and the glassy properties at low temperature. Charge order and charge disproportionation which occur in organic materials resulting from correlation effects are analysed. Experiments under magnetic field, and more specifically field-induced CDWs are discussed. Properties of meso-and nanostructures of CDWs are also reviewed.
397 citations
238 citations