Pressure tunable quantum anomalous Hall states in a topological antiferromagnet

TL;DR

This study demonstrates that applying hydrostatic pressure can reversibly enhance and control quantum anomalous Hall states in antiferromagnetic topological insulators MnBi2Te4, linking mechanical modulation with topological and magnetic phase manipulation.

Contribution

It reveals that moderate hydrostatic pressure can stabilize and control QAH phases in MnBi2Te4, providing a new method for tuning topological states via mechanical means.

Findings

Pressure enhances QAH phase robustness in MnBi2Te4.

Reversible control of magnetic and topological phases with pressure.

Stronger hybridization between layers drives topological states.

Abstract

Mechanical modulation of the lattice parameter can modify the electronic structure and manipulate the magnetic coupling of a material without introducing impurities. Inspired by success in pressure-controlled magnetism, we investigate the effect of hydrostatic pressure on quantized Chern states in the antiferromagnetic topological insulator MnBi2Te4, using transport as a probe. We show that pressure can enhance the robustness of quantum anomalous Hall (QAH) phases that are otherwise delicate in 7SL MnBi2Te4 and in the spin-flop (SF) state of 8SL MnBi2Te4. We explain our findings using a coupled Dirac cone model of MnBi2Te4, which identifies stronger hybridization between van der Waals layers as the driver of topological states. We further demonstrate that moderate pressures readily available in laboratory systems can provide reversible control of magnetic and topological phases. Our results reveal a strong connection between the mechanical engineering of band topology and magnetism.