Two-Dimensional Room-Temperature Ferromagnetic Semiconductors with Quantum Anomalous Hall Effect

To obtain room-temperature ferromagnetic semiconductors and to realize the room-temperature quantum anomalous Hall effect (QAHE) have been big challenges for a long time. Here we report that, on the basis of first-principles calculations, PdBr3, PtBr3, PdI3, and PtI3 monolayers are ferromagnetic semiconductors that could exhibit a high-temperature QAHE. The Curie temperatures estimated by Monte Carlo simulations are 350 and 375 K for PdBr3 and PtBr3 monolayers, respectively. The band gaps of PdBr3 and PtBr3 are found to be 58.7 and 28.1 meV, respectively, with the generalized-gradient approximation and 100.8 and 45 meV, respectively, with the HSE06 method, being quite well in favor of observing the room-temperature QAHE. It is shown that the large band gaps are induced from multiorbital electron correlations. By carefully studying the stabilities of the four aforementioned monolayers, we unveil that they could be feasible for use in experiments. The present work sheds light on the development of spintronic devices by use of room-temperature ferromagnetic semiconductors and the implementation of dissipationless devices by application of the room-temperature QAHE.