Weyl node with random vector potential

TL;DR

This paper investigates how different types of disorder affect Weyl semimetals, revealing a disorder-induced phase transition and contrasting behaviors depending on the nature of the vector potential disorder.

Contribution

It derives renormalization group equations for Weyl semimetals with generic disorder and verifies phase transition predictions through numerical simulations.

Findings

Disorder induces a phase transition from pseudo-ballistic to diffusive behavior.

Pure single-component vector potential disorder does not lead to a diffusive phase.

Numerical results support the theoretical phase transition predictions.

Abstract

We study Weyl semimetals in the presence of generic disorder, consisting of a random vector potential as well as a random scalar potential. We derive renormalization group flow equations to second order in the disorder strength. These flow equations predict a disorder-induced phase transition between a pseudo-ballistic weak-disorder phase and a diffusive strong-disorder phase for sufficiently strong random scalar potential or for a pure three-component random vector potential. We verify these predictions using a numerical study of the density of states near the Weyl point and of quantum transport properties at the Weyl point. In contrast, for a pure single-component random vector potential the diffusive strong-disorder phase is absent.