Electronic States and Magnetic Response of MnBi 2 Te 4 by Scanning Tunneling Microscopy and Spectroscopy

• Published in: Nano letters 2020-05, Vol.20 (5), p.3271-3277
• Main Authors: Yuan, Yonghao, Wang, Xintong, Li, Hao, Li, Jiaheng, Ji, Yu, Hao, Zhenqi, Wu, Yang, He, Ke, Wang, Yayu, Xu, Yong, Duan, Wenhui, Li, Wei, Xue, Qi-Kun
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.0c00031

Exotic quantum phenomena have been demonstrated in recently discovered intrinsic magnetic topological insulator MnBi Te . At its two-dimensional limit, the quantum anomalous Hall effect and axion insulator state were observed in odd and even layers of MnBi Te , respectively. Here, we employ low-temperature scanning tunneling microscopy to study the electronic properties of MnBi Te . The quasiparticle interference patterns indicate that the electronic structures on the topmost layer of MnBi Te are different from those of the expected out-of-plane A-type antiferromagnetic phase. The topological surface states may be embedded in deeper layers beneath the topmost surface. Such novel electronic structure is presumably related to the modification of crystalline structure during sample cleaving and reorientation of the magnetic moment of Mn atoms near the surface. Mn dopants substituted at the Bi site on the second atomic layer are observed. The electronic structures fluctuate at atomic scale on the surface, which can affect the magnetism of MnBi Te .