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arXiv · 2004.06895

Coexistence of Surface Ferromagnetism and Gapless Topological State in MnBi$_2$Te$_4$

D. Nevola·H. X. Li·J. -Q. Yan·R. G. Moore·H. -N. Lee·H. Miao·P. D. Johnson
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Abstract

Surface magnetism and its correlation with the electronic structure are critical to understand the gapless topological surface state in the intrinsic magnetic topological insulator MnBi$_2$Te$_4$. Here, using static and time resolved angle-resolved photoemission spectroscopy (ARPES), we find a significant ARPES intensity change together with a gap opening on a Rashba-like conduction band. Comparison with a model simulation strongly indicates that the surface magnetism on cleaved MnBi$_2$Te$_4$ is the same as its bulk state. The coexistence of surface ferromagnetism and a gapless TSS uncovers the novel complexity of MnBi$_2$Te$_4$ that may be responsible for the low quantum anomalous Hall temperature of exfoliated MnBi$_2$Te$_4$.

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D. Nevola, H. X. Li, J. -Q. Yan, R. G. Moore, H. -N. Lee, H. Miao, P. D. Johnson. 2020-04-15. Coexistence of Surface Ferromagnetism and Gapless Topological State in MnBi$_2$Te$_4$. https://doi.org/10.1103/physrevlett.125.117205

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