Origins of electronic bands in the antiferromagnetic topological insulator MnBi2Te4

Chenhui Yan, Sebastian Fernandez-Mulligan, Ruobing Mei, Seng Huat Lee, Nikola Protic, Rikuto Fukumori, Binghai Yan, Chaoxing Liu, Zhiqiang Mao, Shuolong Yang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Despite the rapid progress in understanding the first intrinsic magnetic topological insulator MnBi2Te4, its electronic structure remains a topic under debates. Here we perform a thorough spectroscopic investigation into the electronic structure of MnBi2Te4 via laser-based angle-resolved photoemission spectroscopy. Through quantitative analysis, we estimate an upper bound of 3 meV for the gap size of the topological surface state. Furthermore, our circular dichroism measurements reveal band chiralities for both the topological surface state and quasi-2D bands, which can be well reproduced in a band hybridization model. A numerical simulation of energy-momentum dispersions based on a four-band model with an additional step potential near the surface provides a promising explanation for the origin of the quasi-2D bands. Our study represents a solid step forward in reconciling the existing controversies in the electronic structure of MnBi2Te4, and provides an important framework to understand the electronic structures of other relevant topological materials MnBi2nTe3n+1.

Original languageEnglish (US)
Article numberL041102
JournalPhysical Review B
Volume104
Issue number4
DOIs
StatePublished - Jul 15 2021

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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