Prediction of Room-Temperature Ferromagnetic Semiconductors in CrMoA2B2 (A = Se and Te; B = Br and I) Monolayers

Room-temperature (RT) ferromagnetic semiconductors can be used to construct new information devices, which will significantly promote the performance of applications. However, the experimental realization of such semiconductors is rarely reported and is restricted by the understanding of the intrinsic mechanism. In this sense, theoretical predictions which can provide candidates of RT ferromagnetic semiconductors for experiments are highly desired. Here, in this paper, we reported that the CrMoSe2Br2 monolayer is a potential RT ferromagnetic semiconductor, which is constructed by introducing Mo atoms to substitute half of Cr atoms in the CrAB monolayers. The dynamic and thermal stabilities of the alloyed monolayers are confirmed by phonon calculations and ab initio MD simulations. Electronic structures show that the CrMoSe2Br2 monolayer is semiconducting with a moderate direct energy gap. Monte Carlo simulations based on the the Heisenberg model present that introducing Mo atoms significantly increases the FM couplings, and the estimated Curie temperature is about 480 K in CrMoSe2Br2. Thus, the excellent electronic and magnetic properties endow the CrMoSe2Br2 monolayer with great potential in future information devices.