Magnetization-tuned topological quantum phase transition in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>MnBi</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Te</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math> devices

Abstract

Recently, the intrinsic magnetic topological insulator ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ has attracted enormous research interest due to the great success in realizing exotic topological quantum states, such as the quantum anomalous Hall effect, the axion insulator state, and high-Chern-number and high-temperature Chern insulator (CI) 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 CI to magnetic insulator with gapped Dirac surface states in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ devices. Specifically, as the magnetic field is tilted away from the out-of-plane direction by \ensuremath{\sim}40--60 \ifmmode^\circ\else\textdegree\fi{}, the Hall resistance deviates from the quantization value, and a colossal, anisotropic magnetoresistance is detected. Theoretical analyses based on modified Landauer-B\"uttiker formalism show that the field-tilt-driven switching from the ferromagnetic state to the canted antiferromagnetic state induces a topological quantum phase transition from CI to magnetic insulator with gapped Dirac surface states in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ devices. These findings reveal a kind of topological phase transition associated with magnetism and spin-orbit coupling. In this letter, we suggest that ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ is an ideal platform for exploring topological quantum phase transitions, and it provides an efficient means for modulating topological quantum states and topological quantum phase transitions.

Topics & Concepts