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 CrMoSe 2 Br 2 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 CrMoSe 2 Br 2 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 CrMoSe 2 Br 2 . Thus, the excellent electronic and magnetic properties endow the CrMoSe 2 Br 2 monolayer with great potential in future information devices.

The pristine 2D CrSe monolayer possesses obvious ferromagnetic (FM) metal properties at temperatures below 280 K. Some chemical groups, such as F, H, and O, are unavoidably adsorbed on the surfaces of the 2D materials in the chemical vapor depositiongrown process. In this work, we systematically study the electronic and magnetic properties of 2D CrSe monolayer derivations by first principles calculation. This indicates that CrSe monolayer derivations are transformed into FM half metals when Cr1 atoms are unilaterally saturated with F, H, and O chemical groups. Meanwhile, both of the surfaces are saturated with chemical groups (i.e., −H and −O), and the FM half metal character is also maintained in this case. More importantly, the Curie temperature of the CrSe monolayer derivations is enhanced to as high as ∼530 K by Monte Carlo simulations. Thus, our results show that the CrSe derivation monolayers have great potential application in the spintronics industry.

No abstract

No abstract

No abstract