Topological Dirac surface states in ternary compounds GeBi 2 Te 4 , SnBi 2 Te 4 and Sn 0.571 Bi 2.286 Se 4 *

作者：Yunlong Li, Chaozhi Huang, Guohua Wang, Jiayuan Hu, Shaofeng Duan, Chenhang Xu, Lu Qi, Qiang Jing, Wentao Zhang, Dong Qian · 发表于：Chinese Physics B · 年份：2021 · DOI：10.1088/1674-1056/ac2b92 · 被引用次数：14 · 研究领域：Topological Materials and Phenomena、Graphene research and applications、Quantum Mechanics and Non-Hermitian Physics

Using high-resolution angle-resolved and time-resolved photoemission spectroscopy, we have studied the low-energy band structures in occupied and unoccupied states of three ternary compounds GeBi 2 Te 4 , SnBi 2 Te 4 and Sn 0.571 Bi 2.286 Se 4 near the Fermi level. In previously confirmed topological insulator GeBi 2 Te 4 compounds, we confirmed the existence of the Dirac surface state and found that the bulk energy gap is much larger than that in the first-principles calculations. In SnBi 2 Te 4 compounds, the Dirac surface state was observed, consistent with the first-principles calculations, indicating that it is a topological insulator. The experimental detected bulk gap is a little bit larger than that in calculations. In Sn 0.571 Bi 2.286 Se 4 compounds, our measurements suggest that this nonstoichiometric compound is a topological insulator although the stoichiometric SnBi 2 Se 4 compound was proposed to be topological trivial.