Topological phase transitions induced by tunable magnetization direction in Chern insulators

Quantum anomalous Hall effect (QAHE), the quantum Hall effect without Landau levels, has been widely studied in 2D electron systems for its nontrivial topology and promising applications in future technology. Magnetic topological insulators are very typical systems exhibiting QAH phase [1].
With recent intense study of spintronics such as spin-orbit torque (SOT) or spin-transfer torque (STT), SOT or STT is anticipated as a proper way to manipulate the magnetization direction and trigger the topological phase transitions [2]. Following the preceding idea, we present a 2D QAHE system, possibly realizable in semiconductor heterostructure, with inversion symmetry breaking and Dresselhaus spin-orbit coupling (SOC).
Topological phase diagrams are obtained by the calculation of Chern number in a totally analytical way. We find that this system is topologically trivial with in-plane magnetization and undergoes a topological phase transition that makes this system transform into a topologically nontrivial phase when the magnetization is deviated from the in-plane direction. Therefore, the control of the topological phases and corresponding chiral edge states can be achieved by tuning the magnetization degrees of freedom.

[1] Science 329 (5987), 61-64.
[2] Nat. Commun. 8, 1479 (2017).