Experimental observation of the gate-controlled reversal of the anomalous Hall effect in the intrinsic magnetic topological insulator MnBi2Te4 device

TL;DR

This study demonstrates gate-controlled reversal of the anomalous Hall effect in MnBi2Te4, revealing a new switching mechanism that could enable topological spin field-effect transistors.

Contribution

We observed and explained the gate-controlled reversal of the anomalous Hall effect in an intrinsic magnetic topological insulator, highlighting a novel switching behavior.

Findings

Reversal of AHE observed with gate tuning.

Reversal occurs inside the Dirac gap.

Reversal linked to Berry curvature and skew scattering.

Abstract

Here we report the reserved anomalous Hall effect (AHE) in the 5-septuple-layer van der Waals device of the intrinsic magnetic topological insulator MnBi2Te4. By employing the top/bottom gate, a negative AHE loop gradually decreases to zero and changes to a reversed sign. The reversed AHE exhibits distinct coercive fields and temperature dependence from the previous AHE. It reaches the maximum inside the gap of the Dirac cone. The newly-seen reversed AHE is attributed to the competition of the intrinsic Berry curvature and the Dirac-gap enhanced extrinsic skew scattering. Its gate-controlled switching contributes a scheme for the topological spin field-effect transistors.