Magnetization-tuned topological quantum phase transition in MnBi2Te4 devices

TL;DR

This paper demonstrates a magnetization-controlled topological quantum phase transition in MnBi2Te4 devices, switching between Chern insulator and magnetic insulator states through angle-dependent magnetic field manipulation.

Contribution

It reveals a magnetization-tuned topological phase transition in MnBi2Te4, combining experimental transport measurements with theoretical analysis to control topological states.

Findings

Detection of a transition from Chern insulator to magnetic insulator with gapped Dirac surface states

Observation of colossal, anisotropic magnetoresistance during the transition

Theoretical modeling confirms the role of magnetic state changes in topological phase transition

Abstract

Recently, the intrinsic magnetic topological insulator MnBi2Te4 has attracted enormous research interest due to the great success in realizing exotic topological quantum states, such as the quantum anomalous Hall effect (QAHE), axion insulator state, high-Chern-number and high-temperature Chern insulator states. One key issue in this field is to effectively manipulate these states and control topological phase transitions. Here, by systematic angle-dependent transport measurements, we reveal a magnetization-tuned topological quantum phase transition from Chern insulator to magnetic insulator with gapped Dirac surface states in MnBi2Te4 devices. Specifically, as the magnetic field is tilted away from the out-of-plane direction by around 40-60 degrees, the Hall resistance deviates from the quantization value and a colossal, anisotropic magnetoresistance is detected. The theoretical analyses based on modified Landauer-Buttiker formalism show that the field-tilt-driven switching from ferromagnetic state to canted antiferromagnetic state induces a topological quantum phase transition from Chern insulator to magnetic insulator with gapped Dirac surface states in MnBi2Te4 devices. Our work provides an efficient means for modulating topological quantum states and topological quantum phase transitions.