Quantum transport in 3D Weyl semimetals: Is there a metal-insulator transition?

TL;DR

This paper investigates the transport properties of 3D Weyl semimetals with disorder, revealing a disorder-driven transition from insulator to metal and highlighting the non-commuting limits of Fermi energy and scattering rate.

Contribution

It demonstrates a continuous disorder-induced transition in Weyl semimetals and uncovers the non-commuting limits affecting the phase behavior.

Findings

Continuous transition from insulator to metal with increasing disorder

Non-commuting limits of Fermi energy and scattering rate influence conductivity

Existence of a quantum critical point as the insulating state

Abstract

We calculate the transport properties of three-dimensional Weyl fermions in a disordered environment. The resulting conductivity depends only on the Fermi energy and the scattering rate. First we study the conductivity at the spectral node for a fixed scattering rate and obtain a continuous transition from an insulator at weak disorder to a metal at stronger disorder. In the self-consistent Born approximation the scattering rate depends on the Fermi energy. Then it is crucial that the limits of the conductivity for a vanishing Fermi energy and a vanishing scattering rate do not commute. As a result, there is also metallic behavior in the phase with vanishing scattering rate and only a quantum critical point remains as an insulating state.