Topological Electronic Structure and Its Temperature Evolution in Antiferromagnetic Topological Insulator MnBi2Te4

Yujie Chen ,Yingbo Zhang ,Yuanhao Mao ,Lexian Yang ,Shuai Liu ,Lixuan Xu ,Hongyuan Wang ,Chen Cheng ,Aiji Liang ,Céphise Cacho ,Chaofan Zhang ,Meixiao Wang ,Yang Wu ,Yiwei Li ,Hao Li ,Yong Xu ,Zhongkai Liu ,Sung Won Jung ,Yanfeng Guo ,Yulin Chen

doi:10.1103/physrevx.9.041040

Abstract

Topological quantum materials coupled with magnetism can provide a platform for realizing rich exotic physical phenomena, including quantum anomalous Hall effect, axion electrodynamics and Majorana fermions. However, these unusual effects typically require extreme experimental conditions such as ultralow temperature or sophisticate material growth and fabrication. Recently, new intrinsic magnetic topological insulators were proposed in MnBi2Te4-family compounds - on which rich topological effects could be realized under much relaxed experimental conditions. However, despite the exciting progresses, the detailed electronic structures observed in this family of compounds remain controversial up to date. Here, combining the use of synchrotron and laser light sources, we carried out comprehensive and high resolution angle-resolved photoemission spectroscopy studies on MnBi2Te4, and clearly identified its topological electronic structures including the characteristic gapless topological surface states. In addition, the temperature evolution of the energy bands clearly reveals their interplay with the magnetic phase transition by showing interesting differences for the bulk and surface states, respectively. The identification of the detailed electronic structures of MnBi2Te4 will not only help understand its exotic properties, but also pave the way for the design and realization of novel phenomena and applications.

Highlights

Topological quantum materials (TQMs) represent special classes of materials whose electronic structures can be characterized by topological invariants protected by certain symmetries, and the breaking of these symmetries can lead to intriguing topological phase transitions
We have presented a systematic investigation of the electronic structure of the AFM-topological insulators (TIs) candidate MnBi2Te4
We observed gapped bulk electronic bands with clear kz dispersion and topological surface states (TSSs) with diminished gap as the characteristic topological electronic structure which is attributed to the neutralized net magnetic moment of domains with different magnetization directions

Summary

Introduction

Topological quantum materials (TQMs) represent special classes of materials whose electronic structures can be characterized by topological invariants protected by certain symmetries, and the breaking of these symmetries can lead to intriguing topological phase transitions. Phases, such as quantum anomalous Hall (QAH) insulators [1,2,3,4], topological axion insulators [5,6,7], magnetic Dirac and Weyl semimetals [8,9,10,11,12,13], and compounds showing Majorana fermions [14]. It is highly urged to search for stoichiometric TQMs with intrinsic magnetic structures for the realization of high-temperature QAH effect and other exotic topological properties

Methods

Results

Conclusion