Vanishing density of states in weakly disordered Weyl semimetals

TL;DR

This paper demonstrates that in weakly disordered Weyl semimetals, rare disorder fluctuations do not generate a finite density of states at the nodal points, preserving their vanishing DoS despite disorder.

Contribution

It provides a rigorous analysis showing that rare disorder states are fragile and do not contribute to a finite DoS, confirming the robustness of Weyl nodes against weak disorder.

Findings

Rare disorder fluctuations do not produce a finite DoS.

The nodal points remain protected under weak disorder.

Fragile states effectively vanish when averaged over disorder.

Abstract

The Brillouin zone of the clean Weyl semimetal contains points at which the density of states (DoS) vanishes. Previous work suggested that below a certain critical concentration of impurities this features is preserved including in the presence of disorder. This result got criticized for its neglect of rare disorder fluctuations which might bind quantum states and hence generate a finite DoS. We here show that in spite of their existence these states are so fragile that their contribution effectively vanishes when averaged over continuous disorder distributions. This means that the integrity of the nodal points remains protected for weak disorder.