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The coupling of topological electronic states and magnetism can lead to various exotic phenomena such as quantum anomalous Hall effect, axion insulating state, etc. Recently, single crystals and thin films of MnBi₂Te₄ have been successfully synthesized and it has been shown to be a promising candidate of antiferromagnetic topological insulator [1, 2]. It is crucial to understand and control the defects in this material as they affect its electronic and magnetic properties. In this talk, I will present our study of the native defects in single-crystalline MnBi₂Te₄ using scanning tunneling microscopy (STM). We identify the dominant defects, Mn_Bi antisites in the second layer of Bi, which may impact the magnetic properties of MnBi₂Te₄ [3, 4, 5]. In addition, we observe another interesting defects with pronounced defect states near the conduction band edge.

1. Otrokov, M. M. et al. Phys. Rev. Lett. 122, 107202 (2019).
2. Gong, Y. et al. Chin. Phys. Lett. 36, 076801 (2019).
3. Yan, J.-Q. et al. Phys. Rev. Mater. 3, 064202 (2019)
4. Yan, J.-Q. et al. arXiv:1905.00400 (2019).
5. Sass, P. M. et al. arXiv:1910.06488 (2019).