Gapless Surface Dirac Cone in Antiferromagnetic Topological Insulator MnBi2Te4

By Yu-Jie Hao, Pengfei Liu, Yue Feng, Xiao-Ming Ma, E. Schwier, M. Arita, Shiv Kumar, Chaowei Hu, R. Lu, M. Zeng and 11 more. Physical Review X, 2019

254 citations recorded by the source corpus.

The recent discovered antiferromagnetic topological insulators in Mn-Bi-Te family with intrinsic magnetic ordering have rapidly drawn broad interest since its cleaved surface state is believed to be gapped, hosting the unprecedented axion states with half-integer quantum Hall effect. Here, however, we show unambiguously by using high-resolution angle-resolved photoemission spectroscopy that a gapless Dirac cone at the (0001) surface of MnBi$_2$Te$_4$ exists between the bulk band gap. Such unexpected surface state remains unchanged across the bulk Neel temperature, and is even robust against severe surface degradation, indicating additional topological protection. Through symmetry analysis and $\textit{ab}$-$\textit{initio}$ calculations we consider different types of surface reconstruction of the magnetic moments as possible origins giving rise to such linear dispersion. Our results reveal that the intrinsic magnetic topological insulator hosts a rich platform to realize various topological phases such as topological crystalline insulator and time-reversal-preserved topological insulator, by tuning the magnetic configurations.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/462546a100ecb562bf26265fa26edbd4f163da13

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In Atomic and Molecular Physics, and Optics

1. H. Ding
2. T. Qian
3. H. Weng

In Condensed Matter Physics

1. H. Weng
2. T. Qian
3. H. Ding

In Materials Chemistry

1. H. Ding
2. T. Qian
3. H. Weng
4. Yuanfeng Xu

Citations in the corpus

• Angle-resolved photoemission studies of quantum materials (2020, unknown): “It seems likely that these discrepant results are attributed to a hν-dependent photoemission cross-section for the surface states (Chen et al., 2019a; Hao et al., 2019).”
• Dirac Surface States in Intrinsic Magnetic Topological Insulators EuSn2As2 and MnBi2nTe3n+1 (2019, background): “tronic states are heavily involved in the magnetic order, which may be critical to realize topological quantum phenomena at higher temperatures. Note added: We become aware of similar studies in Ref. [44, 45, 46] and the updated version of Ref. [26] showing the Dirac SSs in MnBi2Te4 when finalizing ”