Experimental observation of gapped topological surface states in Sb-doped MnBi4Te7

• Published in: Applied physics letters Vol. 124; no. 5
• Main Authors: Qiao, Yuxi, Jiang, Zhicheng, Chen, Bo, Tao, Zicheng, Liu, Zhonghao, Zhang, Fayuan, Cho, Soohyun, Liu, Zhengtai, Guo, Yanfeng, Song, Fengqi, Fei, Fucong, Liu, Jishan, Shen, Dawei
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 29.01.2024
• Subjects: Antimony; Energy gap; Ferromagnetism; High temperature; Photoelectric emission; Quantum Hall effect; Topological insulators; Topology
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0187830

The realization of intrinsic magnetic topological insulators offers an ideal platform to investigate high-temperature quantum anomalous Hall effect as well as quantum devices. The family of MnBi2Te4(Bi2Te3)n has been confirmed that it belongs to this system. However, whether there is a bandgap in the surface states remains controversial. In this work, the ferromagnetism in Sb-doped MnBi4Te7 is confirmed by magnetic transport. Utilizing angle-resolved photoemission spectroscopy, we demonstrate the nontrivial topology in Mn(Bi0.7Sb0.3)4Te7 with an energy gap on the MnBi2Te4 termination. As well, we detect distinct topological surface states on two different terminations. Our results provide spectral evidence of an energy gap in the topological surface states.