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

Mingqiang Gu; Jiayu Li; Hongyi Sun; Yufei Zhao; Chang Liu; Jianpeng Liu; Haizhou Lu; Qihang Liu

doi:10.1038/s41467-021-23844-z

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

Nat Commun. 2021 Jun 10;12(1):3524. doi: 10.1038/s41467-021-23844-z.

Authors

Mingqiang Gu^#¹, Jiayu Li^#¹, Hongyi Sun¹, Yufei Zhao¹, Chang Liu¹, Jianpeng Liu^{2

3}, Haizhou Lu¹, Qihang Liu^{4

5

6}

Affiliations

¹ Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China.
² School of Physical Science and Technology, ShanghaiTech University, Shanghai, China. liujp@shanghaitech.edu.cn.
³ ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, China. liujp@shanghaitech.edu.cn.
⁴ Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China. liuqh@sustech.edu.cn.
⁵ Guangdong Provincial Key Laboratory for Computational Science and Material Design, Southern University of Science and Technology, Shenzhen, China. liuqh@sustech.edu.cn.
⁶ Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China. liuqh@sustech.edu.cn.

^# Contributed equally.

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 the long-sought axion insulators in realistic material systems.