Non-linear conductivity of charge-density-wave systems

TL;DR

This paper investigates the non-linear electrical conductivity of charge-density-wave systems with disorder, revealing a strong-coupling regime near the pinning threshold and distinct phase and velocity scaling behaviors.

Contribution

It introduces a self-consistent approximation scheme for analyzing sliding charge-density-waves beyond standard methods, with explicit 3D calculations and new insights into conductivity regimes.

Findings

Identification of a strong-coupling regime near the pinning threshold

Different scaling of phase and velocity correlations in high-field regime

Presence of narrow-band noise during sliding

Abstract

We consider the problem of sliding motion of a charge-density-wave subject to static disorder within an elastic medium model. Starting with a field-theoretical formulation, which allows exact disorder averaging, we propose a self-consistent approximation scheme to obtain results beyond the standard large-velocity expansion. Explicit calculations are carried out in three spatial dimensions. For the conductivity, we find a strong-coupling regime at electrical fields just above the pinning threshold. Phase and velocity correlation functions scale differently from the high-field regime, and static phase correlations converge to the pinned-phase behaviour. The sliding charge-density-wave is accompanied by narrow-band noise.