Dirac Surface States in Intrinsic Magnetic Topological Insulators EuSn2As2 and MnBi2nTe3n+1

By Hang Li, Shunye Gao, Shaofeng Duan, Yuanfeng Xu, Kejing Zhu, Shangjie Tian, Jianzhong Gao, Wenhui Fan, Z. Rao, Jierui Huang and 17 more. Physical Review X, 2019

186 citations recorded by the source corpus.

In magnetic topological insulators (TIs), the interplay between magnetic order and nontrivial topology can induce fascinating topological quantum phenomena, such as the quantum anomalous Hall effect, chiral Majorana fermions and axion electrodynamics. Recently, a great deal of attention has been focused on the intrinsic magnetic TIs, where disorder effects can be eliminated to a large extent, which is expected to facilitate the emergence of topological quantum phenomena. In despite of intensive efforts, experimental evidence of the topological surface states (SSs) remains elusive. Here, by combining first-principles calculations and angle-resolved photoemission spectroscopy (ARPES) experiments, we have revealed that EuSn2As2 is an antiferromagnetic TI with observation of Dirac SSs consistent with our prediction. We also observe nearly gapless Dirac SSs in antiferromagnetic TIs MnBi2nTe3n+1 (n = 1 and 2), which were absent in previous ARPES results. These results provide clear evidence for nontrivial topology of these intrinsic magnetic TIs. Furthermore, we find that the topological SSs show no observable changes across the magnetic transition within the experimental resolution, indicating that the magnetic order has quite small effect on the topological SSs, which can be attributed to weak hybridization between the localized magnetic moments, from either 4f or 3d orbitals, and the topological electronic states. This provides insights for further research that the correlations between magnetism and topological states need to be strengthened to induce larger gaps in the topological SSs, which will facilitate the realization of topological quantum phenomena at higher temperatures.

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

View Paper: https://www.semanticscholar.org/paper/038536be91c8395056b93e099a6fd33c6c816faf

Citations in the corpus

• Angle-resolved photoemission studies of quantum materials (2020, unknown): “A recent development which promises to shed light on this issue was the prediction of MnBi2Te4 as an antiferromagnetic TI (Li et al., 2019b; Otrokov et al., 2019; Zhang et al., 2019a), with the first published ARPES results reporting a gap of ∼ 100 meV (Lee et al., 2019; Vidal et al., 2019; Zeugner…”