Weyl semimetal/insulator transition from holography

TL;DR

This paper presents a holographic model demonstrating a first-order quantum phase transition from a Weyl semimetal to an insulator, characterized by a hard gap and nonzero anomalous Hall conductivity, revealing complex strongly interacting phase structures.

Contribution

It introduces a holographic framework capturing the Weyl semimetal/insulator transition with a first-order phase change and novel phase structure insights.

Findings

Insulating phase exhibits a hard gap in conductivity.

Anomalous Hall conductivity remains nonzero at zero frequency.

Transition is always first order with a discontinuous change.

Abstract

We study a holographic model which exhibits a quantum phase transition from the strongly interacting Weyl semimetal phase to an insulating phase. In the holographic insulating phase there is a hard gap in the real part of frequency dependent diagonal conductivities. However, the anomalous Hall conductivity is nonzero at zero frequency, indicting that it is a Chern insulator. This holographic quantum phase transition is always of first order, signified by a discontinuous anomalous Hall conductivity at the phase transition, in contrast to the very continuous holographic Weyl semimetal/trivial semimetal phase transition. Our work reveals the novel phase structure of strongly interacting Weyl semimetal.