arXiv subjects

Anatoley T. Zheleznyak

Publications and source records attributed to Anatoley T. Zheleznyak.

9 recordsLinked to original sources

arXiv2018

Photoinduced Screening Breakdown Mediated by Plasmon Excitations and Potential Instabilities in the System

In this work, we estimate the effect of photoinduced screening breakdown of the Coulomb potential mediated by plasmons. In contrast to previous studies, we consider the contribution from the divergence of renormalized inverse electron permittivity, which enhances Coulomb interaction at longer ranges. Our work reveals that the Coulomb potential acquires oscillating terms, which for the charged plane case could lead to a spatial heterostructure. In the resonant case ($ω_p = Ω$), photoinduced Coulomb interaction becomes attractive for small values of momenta. This Coulomb interaction renormalization could potentially lead to instabilities in the electron system, such as superconductivity and/or charge density waves. We found possible divergence of the electron coupling constant and discuss herein a potential new mechanism of superconductivity based on electron-electron interaction renormalization via the plasmon oscillating electric field. We also briefly discuss possible photoinduced $ε$ near zero conditions.

cond-mat.str-el↗

arXiv2000

Comparison of experimental data and theoretical calculations for electrical resistivity and Hall coefficient in quasi-one-dimensional organic conductor (TMTSF)2PF6

The temperature dependences of the Hall coefficient and electrical resistivity recently measured by Moser et al. [Phys. Rev. Lett. 84, 2674 (2000)] in the quasi-one-dimensional organic conductor (TMTSF)2PF6 are quantitatively compared with our previous theoretical calculations [Synth. Met. 103, 2202 (1999); Eur. Phys. J. B 11, 385 (1999)]. We find a good agreement, albeit not with a fully consistent set of parameters for the two quantities, without appealing to the Luttinger liquid concept.

cond-mat.str-el↗

arXiv1999

Anomalous temperature dependence of resistivity in quasi-one-dimensional conductors in a strong magnetic field

We present a heuristic, semiphenomenological model of the anomalous temperature (T) dependence of resistivity Rxx recently observed experimentally in the quasi-one-dimensional (Q1D) organic conductors of the (TMTSF)2X family in moderately strong magnetic fields. We suggest that a Q1D conductor behaves like an insulator (dRxx/dT<0), when its effective dimensionality is one, and like a metal (dRxx/dT>0), when its effective dimensionality is greater than one. Applying a magnetic field reduces the effective dimensionality of the system and switches the temperature dependence of resistivity between the insulating and metallic laws depending on the magnitude and orientation of the magnetic field. We critically analyze whether various microscopic models suggested in literature can produce such a behavior and find that none of the models is fully satisfactory. In particular, we perform detailed analytical and numerical calculations within the scenario of magnetic-field-induced spin-density-wave precursor effect suggested by Gor'kov and find that the theoretical results do not agree with the experimental observations.

cond-mat↗

arXiv1998

Temperature dependence of the normal-state Hall coefficient of a quasi-one-dimensional metal

We develop a systematic theory of the Hall effect in Q1D conductors in both weak and strong magnetic fields for a model where the electron relaxation time varies over the Fermi surface. At high temperatures, the Hall coefficient saturates at the value $-β/ecn$, where the dimensionless coefficient $β$ is determined by the curvature of the longitudinal dispersion law of electrons, $e$ the electron charge, $c$ is the speed of light, and $n$ is the hole concentration. At low temperatures, where a strong variation of the relaxation rate over the Fermi surface develops in the form of ``hot spots'', the Hall coefficient becomes temperature-dependent and may change sign for a particular choice of the transverse dispersion law parameters. In our model, the sign changes in a weak, but not in a strong magnetic field.

cond-mat↗

arXiv1998

Magnetoresistance of YBa2Cu3O7 in the "cold spots" model

We calculate the in-plane magnetoresistance $Δρ_{xx}/ρ_{xx}$ of YBa$_2$Cu$_3$O$_7$ in a magnetic field applied perpendicular to the $CuO_2$ planes for the ``cold spots'' model. In this model, the electron relaxation time $τ_2\propto1/T^2$ at small regions on the Fermi surface near the Brillouin zone diagonals is much longer than the relaxation time $τ_1\propto1/T$ at the rest of the Fermi surface ($T$ is temperature). In qualitative agreement with the experiment, we find that Kohler's rule is strongly violated, but the ratio $Δρ_{xx}/ρ_{xx}\tan^2θ_H$, where $\tanθ_H$ is the Hall angle, is approximately temperature-independent. We find the ratio is about 5.5, which is of the same order of magnitude as in the experiment.

cond-mat.supr-con↗

arXiv1998

Magnetic-field-induced Luttinger insulator state in quasi-one-dimensional conductors

We present a heuristic, semiphenomenological model of the anomalous temperature (T) dependence of resistivity $ρ_{xx}$ recently observed experimentally in the quasi-one-dimensional (Q1D) organic conductors of the (TMTSF)2X family in moderately strong magnetic fields. We suggest that a Q1D conductor behaves like an insulator ($dρ_{xx}/dT<0$), when its effective dimensionality is one, and like a metal ($dρ_{xx}/dT>0$), when its effective dimensionality is greater than one. Applying a magnetic field reduces the effective dimensionality of the system and switches the temperature dependence of resistivity between the insulating and metallic laws depending on the magnitude of the magnetic field and its orientation along the ``magic'' and ``nonmagic'' angles.

cond-mat.str-el↗

arXiv1997

Phenomenological interpretations of the ac Hall effect in the normal state of YBa2Cu3O7

Ac and dc magnetotransport data in the normal state of YBa2Cu3O7 are analyzed within Fermi-liquid and non-Fermi-liquid models. In the Fermi-liquid analysis we use the Fermi surface deduced from band structure calculations and angular resolved photoemission experiments and assume that the electron relaxation rate varies over the Fermi surface. The non-Fermi-liquid models are the two-dimensional Luttinger liquid model and the charge-conjugation-symmetry model. We find that the existing experimental data can be adequately fitted by any of these models. This work provides a framework for the analysis of experiments that may discriminate among these models.

cond-mat.supr-con↗

arXiv1996

Parquet solution for a flat Fermi surface

We study instabilities occurring in the electron system whose Fermi surface has flat regions on its opposite sides. Such a Fermi surface resembles Fermi surfaces of some high-$T_c$ superconductors. In the framework of the parquet approximation, we classify possible instabilities and derive renormalization-group equations that determine the evolution of corresponding susceptibilities with decreasing temperature. Numerical solutions of the parquet equations are found to be in qualitative agreement with a ladder approximation. For the repulsive Hubbard interaction, the antiferromagnetic (spin-density-wave) instability dominates, but when the Fermi surface is not perfectly flat, the $d$-wave superconducting instability takes over.

cond-mat↗

arXiv1995

``Hot Spots'' in Quasi-One-Dimensional Organic Conductors

Distribution of the electron scattering rate on the Fermi surface of a quasi-one-dimensional conductor is calculated for the electron-electron umklapp interaction. We find that in certain regions on the Fermi surface the scattering rate is anomalously high. The reason for the existence of these ``hot spots'' is analogous to the appearance of the van Hove singularities in the density of states. We employ a generalized $τ$-approximation (where the scattering integral in the Boltzmann equation is replaced by the scattering time which depends on the position at the Fermi surface) to study the dependence of the electric resistance on the amplitude and the orientation of a magnetic field. We find that the ``hot spots'' do not produce a considerable magnetoresistance or commensurability effects at the so-called ``magic angles''.

cond-mat↗