Exchange-Driven Chern States in High-Mobility Intrinsic Magnetic Topological Insulators

Su Kong Chong, Chao Lei, Yang Cheng, Seng Huat Lee, Zhiqiang Mao, Allan H. Macdonald, Kang L. Wang

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The layer-dependent Chern number (C) in MnBi2Te4 is characterized by the presence of a Weyl semimetal state in the ferromagnetic coupling. However, the influence of a key factor, namely, the exchange coupling, remains unexplored. This study focuses on characterizing the C=2 state in MnBi2Te4, which is classified as a higher C state resulting from the anomalous n=0 Landau levels (LLs). Our findings demonstrate that the exchange coupling parameter strongly influences the formation of this Chern state, leading to a competition between the C=1 and 2 states. Moreover, the emergence of odd-even LL sequences, resulting from the breaking of LL degeneracy, provides compelling evidence for the strong exchange coupling strength. These findings highlight the significance of the exchange coupling in understanding the behavior of Chern states and LLs in magnetic quantum systems.

Original languageEnglish (US)
Article number146601
JournalPhysical review letters
Volume132
Issue number14
DOIs
StatePublished - Apr 5 2024

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy

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