Antiferromagnetic topological insulator MnBi₂Te₄

Using ab initio and Monte Carlo calculations we predict the van der Waals layered compound MnBi₂Te₄ to be antiferromagnetic (AFM) topological insulator [1], which is further confirmed experimentally [1]. MnBi₂Te₄ appears to be invariant with respect to the combination of the time-reversal and primitive-lattice translation symmetries, giving rise to the Z₂ topological classification of AFM insulators, and Z₂=1 for MnBi₂Te₄. Its (0001) surface, breaking the combined symmetry, shows a giant gap in the topological surface state thus representing a promising platform for the quantized magnetoelectric effect observation. In the 2D limit, MnBi₂Te₄ shows a unique set of thickness-dependent magnetic and topological transitions, which drive it through FM and (un)compensated AFM phases, as well as quantum anomalous Hall (QAH) and intrinsic zero plateau QAH states [2].

[1] M. Otrokov et al., arXiv:1809.07389
[2] M. Otrokov et al., arXiv:1810.05289