Indexed by: Journal paper

First Author: Zuowei Liang

Correspondence Author: X-H Chen,Zhenyu Wang

Co-author: Gang Xu,Zhijun Wang,Tao Wu,J-F He,JJ Ying,Simin Nie,Qiang Zhang,Mengzhu Shi,Aiyun Luo

Journal: Physical Review B

Included Journals: SCI

Discipline: Science

First-Level Discipline: Physics

Document Type: J

Volume: 102

Issue: 16

Page Number: 161115

ISSN No.: 2469-9950

Date of Publication: 2020-10-19

Impact Factor: 4.036

Abstract: Nontrivial band topology combined with magnetic order can lead to rich emergent phenomena, including quantized anomalous Hall effect and axion insulator state. Here we use scanning tunneling microscopy to image the surface Dirac fermions of the newly discovered magnetic topological insulators Mn Bi 2 Te 4 and Mn Bi 4 Te 7. We have determined the energy dispersion and helical spin texture of the surface states through quasiparticle interference patterns far above Dirac energy. Approaching the Dirac point, the native defects in the Mn Bi 2 Te 4 septuple layer give rise to resonance states which extend spatially and potentially hinder the detection of a mass gap in the spectra. Our results impose tight constraints on the magnitude of the possible mass gap at the nanoscale and provide key ingredients for a comprehensive understanding of the electronic structure in this class of fascinating materials.