An intrinsic magnetic topological insulator MnBi₂Te₄ has been discovered recently, in which the quantum anomalous Hall effect has been realized. However, the detection of magnetism as well as topological states on its surface is still controversial. We obtained high-quality MnBi₂Te₄ film by molecular beam epitaxy and study its electronic structures by scanning tunneling microscopy (STM) and angle resolved photoemission spectroscopy [1, 2]. Based on our results, we propose a novel layered surface structure of MnBi₂Te₄, which can explain the current controversies in experimental results. In the second part of my talk, I will show our direct STM observation of Majorana bound states in a new transition metal dichalcogenide WS₂ [3].


Reference:
[1] Yan Gong et al., Experimental realization of an intrinsic magnetic topological insulator. Chin. Phys. Lett. 36, 076801 (2019).
[2] Yonghao Yuan et al., Electronic states and magnetic response of MnBi₂Te₄ by scanning tunneling microscopy and spectroscopy. Nano Lett. 20, 3271-3277 (2020).
[3] Yonghao Yuan et al., Evidence of anisotropic Majorana bound states in WS₂, Nature Physics 15, 1046-1051 (2019).