Global phase diagram of Coulomb-interacting anisotropic Weyl semimetals with disorder

TL;DR

This paper investigates how disorder and Coulomb interactions influence the phase diagram of three-dimensional anisotropic Weyl semimetals, revealing that Coulomb interactions significantly alter the critical disorder strength for phase transitions.

Contribution

It demonstrates that Coulomb interactions, despite being irrelevant in clean systems, dramatically affect disorder-driven phase transitions in anisotropic Weyl semimetals.

Findings

Weak disorder is irrelevant in clean anisotropic Weyl semimetals.

Disorder induces a transition from semimetal to diffusive metal when above a critical strength.

Coulomb interactions significantly modify the critical disorder strength due to anisotropic screening.

Abstract

Taking into account the interplay between the disorder and Coulomb interaction, the phase diagram of three-dimensional anisotropic Weyl semimetal is studied by renormalization group theory. Weak disorder is irrelevant in anisotropic Weyl semimetal, while the disorder becomes relevant and drives a quantum phase transition from semimetal to compressible diffusive metal phases if the disorder strength is larger than a critical value. The long-range Coulomb interaction is irrelevant in clean anisotropic Weyl semimetal. However, interestingly, we find that the long-range Coulomb interaction exerts a dramatic influence on the critical disorder strength for phase transition to compressible diffusive metal. Specifically, the critical disorder strength can receive a prominent change even though an arbitrarily weak Coulomb interaction is included. This novel behavior is closely related to the anisotropic screening effect of Coulomb interaction,and essentially results from the specifical energy dispersion of the fermion excitations in anisotropic Weyl semimetal. The theoretical results are helpful for understanding the physical properties of the candidates of anisotropic Weyl semimetal, such as pressured BiTeI, and some other related materials.