Bimetal Chalcogenides TM 2 TM'X 4 Monolayer: Stable Room Temperature Ferromagnetic Semiconductors

Abstract

Two-dimensional (2D) ferromagnetic semiconductors (FMSs), which combine ferromagnetism and semiconducting properties, have long been highly desired in the field of spintronics. Here, we predicted a class of stable 2D FMSs based on transition metal chalcogenides by mixing the metal atoms, TM 2 TM'X 4 (TM=V/Ti, TM'=Ni/Ti/V, X=Se/Te). It is revealed that V 2 NiTe 4 monolayer is a bipolar ferrimagnetic (FIM) semiconductor with an indirect bandgap of 0.40 eV, while V 2 TiTe 4 and Ti 2 VSe 4 monolayers are indirect bandgap FMSs with bandgaps of 0.62 eV and 0.24 eV, respectively. Particularly, all the TM 2 TM'X 4 monolayers prefer in-plane magnetization and the magnetic orders can be survived in room temperature with Curie temperatures of 715 K, 347 K and 297 K for V 2 NiTe 4 , V 2 TiTe 4 and Ti 2 VSe 4 monolayer, respectively. Moreover, the electronic and magnetic stabilities are sensitive to biaxial strains. Interestingly, Ti 2 VSe 4 and V 2 NiTe 4 monolayers can be tuned to be room temperature FM half metal under biaxial 3% tensile strain and -6% compressive strain, separately.Our results provide a platform to design promising candidates for spintronic devices.