Spectral signatures of the surface anomalous Hall effect in magnetic axion insulators

TL;DR

This paper investigates the spectral signatures of the surface anomalous Hall effect in magnetic axion insulators, revealing how magnetic and electronic tuning can produce distinct topological phases with observable surface phenomena.

Contribution

It provides a comprehensive analysis of the surface anomalous Hall effect in magnetic topological phases using models and first-principles calculations, linking theory to realistic materials.

Findings

Surface anomalous Hall conductivity in axion insulators is localized and oscillates around e2/2h.

A rich 3D topological phase diagram can be achieved by tuning magnetization and interlayer hopping.

Chiral hinge modes are potential experimental signatures for detecting axion insulators.

Abstract

The topological surface states of magnetic topological systems, such as Weyl semimetals and axion insulators, are associated with unconventional transport properties such as nonzero or half-quantized surface anomalous Hall effect. Here we study the surface anomalous Hall effect and its spectral signatures in different magnetic topological phases using both model Hamiltonian and first-principles calculations. We demonstrate that by tailoring the magnetization and interlayer electron hopping, a rich three-dimensional topological phase diagram can be established, including three types of topologically distinct insulating phases bridged by Weyl semimetals, and can be directly mapped to realistic materials such as MnBi2Te4/(Bi2Te3)n systems. Among them, we find that the surface anomalous Hall conductivity in the axion-insulator phase is a well-localized quantity either saturated at or oscillating around e2/2h, depending on the magnetic homogeneity. We also discuss the resultant chiral hinge modes embedded inside the side surface bands as the potential experimental signatures for transport measurements. Our study is a significant step forward towards the direct realization of long-sought axion insulators in realistic material systems.