Intrinsic layer Hall effect with half-quantization in PT-broken magnetic topological insulators

Abstract

The layer Hall effect (LHE) in antiferromagnetic topological systems originates from layer-locked Berry curvature, which gives rise to opposite Hall responses associated on different layers. Experimentally, in PT-symmetric even-layer MnBi2Te4, a perpendicular electric field is usually required to observe a layer-polarized anomalous Hall conductance. In principle, antiferromagnetic topological materials with intrinsic structural asymmetry provide a relatively simple route to revealing the LHE without external field control. Using first-principles calculations and a tight-binding model, we show that the intrinsic antiferromagnetic topological material MnBi4Te7, which lacks PT-symmetry protection, gives rise to an intrinsic LHE with a half-quantized plateau at σxy=±0.5e2/h, whereas MnBi6Te10 also exhibits a layer-polarized anomalous Hall conductance, although the half-quantized value is not realized. The tight-binding results are in good agreement with the first-principles calculations. Since MnBi4Te7 has been widely synthesized and characterized in experiments, this study provides an optimal platform for exploring the intrinsic LHE with half-quantization without external electric field.