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 MnBi 2 Te 4 bilayer and an Sb 2 Te 3 film is able to harbor the half-quantized Hall (HQH) effect with a ferroelectrically switchable Hall conductivity of ± e 2 /2 h . We first show that, in the energetically stable configuration, the antiferromagnetic MnBi 2 Te 4 bilayer opens a gap in the top surface bands of Sb 2 Te 3 through the proximity effect, while its bottom surface bands remain gapless; consequently, an HQH conductivity of e 2 /2 h can be sustained clockwise or counterclockwise, depending on the antiferromagnetic configuration of the MnBi 2 Te 4 . Remarkably, when interlayer sliding is applied within the MnBi 2 Te 4 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.