Two-Dimensional Transition-Metal Oxides Mn₂O₃Realized the Quantum Anomalous Hall Effect

The quantum anomalous Hall effect is an intriguing topological nontrivial phase arising from spontaneous magnetization and spin-orbit coupling. However, the tremendously harsh realizing requirements of the quantum anomalous Hall effects in magnetic topological insulators of Cr- or V-doped (Bi,Sb)2Te3 films hinder their practical applications. Here, we perform first-principles calculations to predict that three Mn2O3 structures are intrinsic ferromagnetic Chern insulators. Remarkably, a quantum anomalous Hall phase of Chern number C = -2 is found, and there are two corresponding gapless chiral edge states appearing inside the bulk gap. More interestingly, only a small tensile strain is needed to induce the phase transition from the Cmm2 and C222 phases to the P6/mmm phase. Meanwhile, a topological quantum phase transition from a quantum anomalous Hall phase to a trivial insulating phase can be realized. The combination of these novel properties renders the two-dimensional ferromagnet a promising platform for highly efficient electronic and spintronic devices.