Chern number transition of quantum anomalous hall phases in kagome TM3Te4 (TM = Ti, Cr) monolayers by manipulating magnetization orientation

The development of quantum anomalous hall (QAH) insulator with high transition temperature is the key to realize practical applications in future quantum technology and spintronics. Here, we predicted two stable two-dimensional kagome structures, Ti3Te4 and Cr3Te4, and found that both of them are intrinsic QAH insulators, using density functional theory calculations. In the absence of spin-orbit coupling (SOC), both systems display ferromagnetism (FM) Weyl semimetal states. Remarkably, Ti3Te4 monolayer is revealed to be a robust ferromagnetic half metal with high Curie temperature (TC) of 403 K. When the SOC effect occurs, it spontaneously creates QAH states with large nontrivial bandgap and chiral edge states. As a result, the Ti(Cr)3Te4 monolayer is changed to be QAH insulators with Chern number C = +/- 1 by rotation of magnetization orientation. In addition, the phase change from FM QAH insulator to antiferromagnetic insulator can be manipulated by applying external strains. Moreover, a high-Chern number phase (C = 2) arises by building Ti3Te4/MoS2/Ti3Te4 heterostructure. Meanwhile, the topological phase transition can be well recurred by using a spinless three-band tight-binding (TB) model. The findings present ways to realize potential QAH insulators with high transition temperatures.