Phase diagrams of Weyl semimetals with competing intraorbital and interorbital disorders

TL;DR

This paper investigates how intra- and interorbital disorders affect Weyl semimetals, revealing complex phase transitions and the emergence of a diffusive anomalous Hall metal phase through detailed phase diagram analysis.

Contribution

It provides the first comprehensive phase diagrams showing the effects of combined intra- and interorbital disorders on Weyl semimetals, including stability, phase transitions, and the diffusive anomalous Hall metal phase.

Findings

Weyl semimetals are stable against weak intra- and interorbital disorders.

Weak intraorbital disorder can induce a transition from WSM to 3D QAHI.

Weak interorbital disorder can cause WSM-NI transitions and phase changes.

Abstract

A Weyl semimetal (WSM) is a topological material that hosts Weyl fermions as quasiparticles in the bulk. We study the combined effect of intra- and interorbital disorders on WSMs by adopting a tight-binding model that supports the WSM, three-dimensional quantum anomalous Hall insulator (3D QAHI), and normal insulator (NI) phases in the clean limit. Based on the calculation of the localization length and the Hall conductivity, we present rich phase diagrams due to the interplay of intra- and interorbital disorders. We find that the WSM with well-separated Weyl nodes is stable to both weak intra- and interorbital disorders. However, weak intraorbital disorder can gap out a WSM close to the 3D QAHI phase in the clean phase diagram, forming a 3D QAHI, and it can also drive a NI near the WSM phase to a WSM. By contrast, weak interorbital disorder can cause a 3D QAHI-WSM transition for a 3D QAHI in proximity to the WSM phase in the clean limit, and it can annihilate a WSM near the NI phase, bringing about a WSM-NI transition. We observe a diffusive anomalous Hall metal (DAHM) phase at moderate disorder strength. The DAHM appears in a wide range of the phase diagram when the intraorbital disorder dominates over the interorbital disorder, while the DAHM is found to exist in a narrow region or be missing in the phase diagram when the interorbital disorder dominates.