Quantum layer spin Hall effect in sliding antiferromagnetic bilayers

Abstract

Sliding antiferromagnetic bilayers have attracted considerable attention due to their multiferroic properties coupled with layers. Moreover, the interlayer sliding operations in antiferromagnetic bilayers could also result in the layer-polarized anomalous Hall effect (LP-AHE). However, the topological phases coupled with layers in antiferromagnetic bilayers are rarely reported. Our work proposes the quantum layer spin Hall effect (QLSHE) induced by appropriate electronic correlation strength and biaxial strain in sliding antiferromagnetic bilayers. The QLSHE exhibits quantized spin Hall conductivity and helical-like gapless edge states. Though this is similar to the quantum spin Hall effect in monolayers, the QLSHE originates from the coupled Chern insulators with opposite chirality and magnetization. We propose this mechanism in 3R and 2H stacking configurations of bilayer FeX₂ (X = Cl, Br, I) that exhibits valley polarization, sliding ferroelectrics and the LP-AHE. An external electric field also verifies the stability of the QLSHE. Our work explores space potential via layer-dependent topological properties for future quantum device applications.