Designed two dimensional triangle lattice Ti3X5 (X=S, Se): Stable quantum anomalous Hall states with high Chern number

Abstract

Although much efforts have been made into exploration of quantum anomalous Hall (QAH) effects in theory and experiment, the QAH materials with high Chern number are still rare to people. Here, by first-principles calculations, we theoretically predicted stable 2D robust QAH monolayers, Ti3X5 (X = S, Se) with high Chern number |C| = 2. In the absence of spin–orbital coupling (SOC), the ferromagnetism polarizes the system into a half semimetal with eight Weyl points in the whole Brillouin zone. When SOC is turned on, the bandgap is opened with two chiral edge modes. Additionally, a topological phase transition from C = −2 to C = 2 is realized by rotating the magnetization direction from z axis to −z axis. In addition, a phase transition from C = −2 to C = 0 can be manipulated by applying external strains or varying electronic correlation Ueff. Our work provides potential high Chern number QAH candidates for the practical electronic application.