Anomalous Gurzhi effect

TL;DR

This paper explores how the chiral anomaly influences electrical conductivity in Weyl and Dirac semimetals, revealing an unusual nonmonotonic temperature dependence called the anomalous Gurzhi effect under specific conditions.

Contribution

It introduces the concept of the anomalous Gurzhi effect in semimetals and identifies the conditions for its occurrence in clean materials with weak magnetic fields.

Findings

Magnetic-field-dependent conductivity shows nonmonotonic temperature dependence.

The anomalous Gurzhi effect occurs in clean semimetals with dominant electron-electron scattering.

Conditions for conventional Gurzhi effect in 3D Dirac and Weyl semimetals are established.

Abstract

We investigate the role of the chiral anomaly in hydrodynamic and crossover regimes of transport in a Weyl or Dirac semimetal film. We show that the magnetic-field-dependent part of the electric conductivity in the direction of the magnetic field develops an unusual nonmonotonic dependence on temperature dubbed the anomalous Gurzhi effect. This effect is realized in sufficiently clean semimetals subject to a classically weak magnetic field where the electron-electron scattering dominates and the relaxation of the valley-imbalance charge density happens at the boundaries. Moreover, the conditions for the realization of the conventional Gurzhi effect in hydrodynamic and crossover regimes of transport in three-dimensional Dirac and Weyl semimetals are determined.