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

TL;DR

This paper proposes a heuristic model explaining the anomalous temperature dependence of resistivity in quasi-one-dimensional conductors under magnetic fields, highlighting the role of effective dimensionality and analyzing existing microscopic models.

Contribution

It introduces a semiphenomenological model linking resistivity behavior to effective dimensionality changes induced by magnetic fields in Q1D conductors.

Findings

Resistivity switches between insulating and metallic behavior with magnetic field changes.

Existing microscopic models do not fully explain the observed phenomena.

The magnetic-field-induced spin-density-wave scenario does not match experimental data.

Abstract

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.