  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.
