Antiferromagnetism-Induced Spin Splitting in Systems Described by Magnetic Layer Groups

Abstract

In this paper, we report the classification of all the 528 magnetic layer groups into seven spin splitting prototypes, in analogy to the similar classification previously reported for the 1651 magnetic space groups [Yuan et al., Phys. Rev. Mat. 2021, 5, 014409]. According to this classification, induced (Pekar–Rashba) spin splitting is possible in the antiferromagnetic monolayers described by magnetic layer groups of type I (no anti-unitary operations) and III, both in the presence and in the absence of the space inversion operation. As one specific application, we have studied theoretically the (110) monolayer of antiferromagnetic (AFM) MnO2. Our density functional theory calculations for this structure predicted colossal (on the order of 1 eV) spin splitting in the entire Brillouin zone, similar to the case of the (110) monolayer of AFM MnF2 which was studied by us earlier. This splitting is much larger compared to the corresponding values for the bulk AFM1 structure of β-MnO2, which was rationalized by noting that the (110) monolayer is described by the type I magnetic layer group that does not contain anti-unitary symmetry operations, and therefore, spin splitting is not suppressed anywhere in the entire Brillouin zone, including high-symmetry points and lines.