Antiferromagnetic quantum spin Hall insulators with high spin Chern numbers

Topological states in antiferromagnetic (AFM) systems have gained much attention recently. However, general proposals for the realization of a two-dimensional (2D) AFM quantum spin Hall (QSH) insulator are still absent. In this paper, we present a general proposal for 2D AFM QSH insulators by stacking 2D half quantum anomalous Hall insulators in a way that maintains the symmetry of a combination of inversion symmetry and time-reversal symmetry. Depending on the number of stack layers, the obtained AFM QSH insulators can have multiple pairs of dissipationless spin transport channels, revealing the nontrivial implication of high (even) spin Chern numbers (${C}_{s}$). Using two concrete material examples, ${\text{Fe}}_{2}\text{Br}\text{Mg}\text{P}$ monolayer and TiTe bilayer, we show that both intercalation and van der Waals stacks can be used to realize the proposed AFM QSH insulators. The robustness of the gapless edge states and the topological invariants (high ${C}_{s}$) of our AFM QSH insulators have been tested and shown to be robust against diluted magnetic impurities and weak magnetic field. The spin-chirality-spatial locking phenomenon in the edge states and their susceptibility to $z$-direction electric field modulation promote these systems as promising candidates for innovative spintronics applications.