Reconfigurable Magnetotransport in MnBi ₂ Te ₄ via Gate and Magnetic Field Tuning

Abstract

Abstract The intrinsic magnetic topological insulator MnBi 2 Te 4 is a promising platform for exploring quantum phases with nontrivial band topology and for enabling electrical control over coupled magnetic and electronic phase transitions. In‐plane magnetic fields, in particular, offer a distinct means of tuning these properties by strengthening quantized Hall effects, enhancing surface energy gaps, and driving spin reorientation transitions. However, a systematic understanding of how such fields affect magnetotransport is limited. Here, the magnetotransport behavior of few‐layer MnBi 2 Te 4 as a function of gate voltage, temperature, and magnetic field angle, with a primary focus on in‐plane field effects, are investigated. A gate‐tunable crossover in magnetoresistance is observed from positive to negative values under in‐plane magnetic fields as the gate voltage is swept below the charge neutrality point at temperatures below the Néel temperature. The in‐plane field drives a transition from the antiferromagnetic ground state to a ferromagnetic configuration with spins aligned in‐plane, while simultaneously altering the electronic structure, as revealed by gate‐dependent transport features. The angle‐dependent measurements reveal strongly gate‐tunable magnetotransport anisotropy. These results establish in‐plane magnetic fields as an effective tuning parameter for modulating spin and charge transport in MnBi 2 Te 4 , advancing prospects for reconfigurable spintronic and topological devices.