Magnetically and electrically tunable nonlinear Hall effect in Tt-symmetric antiferromagnets

Tt-symmetric antiferromagnets can exhibit multiferroicity with coexisting ferroelectricity and magnetic order, and thus host multiple order-parameter configurations. However, how to electrically read out these configurations is an issue meriting further investigation. Here, by combining tight-binding and first-principles calculations, we propose electrically and magnetically tunable nonlinear Hall transport in ferroelectric Tt-symmetric antiferromagnets. Model calculations show that ferroelectric switching can reverse the sign of the Berry curvature dipole (BCD), whereas the Neel vector rotation modulates its magnitude, allowing both ferroelectric and magnetic order to be reflected in the nonlinear Hall signal. First-principles calculations of the VOCl2 monolayer confirm these behaviors and predict a sizable BCD that gives rise to a potentially detectable Hall voltage. Our findings open up opportunities to integrate electrical and magnetic modulations of the nonlinear Hall effect within a single material, with potential applications in multi-state information encoding and readout in antiferromagnetic spintronics.