Quantum anomalous Hall effect in two dimensional Janus Mn2Cl3Br3 with large magnetic anisotropy energy

Abstract: The quantum anomalous Hall (QAH) effect have been experimentally observed in magnetically-doped topological insulators. However, the QAH effect only at extremely low temperatures due to the weak magnetic coupling, small band gap and low carrier mobility. Here, based on first-principles density functional theory, we predict that the Janus Mn2Cl3Br3 is high Curie temperature ferromagnet that host the QAH phase. Furthermore, we find that it is a Dirac half-metal characterized by a Dirac cone in one spin channel with carrier mobilities comparable to freestanding germanene and an large band gap in other spin channel. Simultaneously, when the spin-orbital coupling interaction is considered, the Janus Mn2Cl3Br3 exhibit lager magnetic anisotropic energy of 11.89 meV/cell and a nontrivial band gap. More interestingly, both the Chern number sign and the chiral edge current are tuned by changing the direction of magnetization. Our finding would suggest the possibility of not only realized the QAH effect but also designed the flow direction of the edge current.