Ferroelectrically Switchable Half-Quantized Hall Effect

Integrating ferroelectricity, antiferromagnetism, and topological quantum transport within a single material is rare but crucial for developing next-generation quantum devices. Here, we propose a multiferroic heterostructure consisting of an antiferromagnetic MnBi2Te4 bilayer and an Sb2Te3 film is able to harbor the half-quantized Hall (HQH) effect with a ferroelectrically switchable Hall conductivity of ± e2/2h. We first show that, in the energetically stable configuration, the antiferromagnetic MnBi2Te4 bilayer opens a gap in the top surface bands of Sb2Te3 through the proximity effect, while its bottom surface bands remain gapless; consequently, an HQH conductivity of e2/2h can be sustained clockwise or counterclockwise, depending on the antiferromagnetic configuration of the MnBi2Te4. Remarkably, when interlayer sliding is applied within the MnBi2Te4 bilayer, its electric polarization direction associated with parity-time reversal symmetry breaking is reversed, accompanied by a reversal of the HQH conductivity. The proposed approach offers a powerful route to control topological quantum transport in antiferromagnetic materials by ferroelectricity.