Two-Dimensional Transition-Metal Oxides Mn<sub>2</sub>O<sub>3</sub> Realized the Quantum Anomalous Hall Effect
Ping Li, Tianyi Cai
Abstract
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.