High curie temperature, large magnetocrystalline anisotropy energy and piezoelectricity in 2D tetrahedral VXCl (X = Te, Se, S) & VMSe2 (M = Al, Ga, In)

Abstract The ferromagnetic semiconducting materials with tetrahedral coordination structure have lower crystal field repulsion energy and variable structure, which would be beneficial to achieve high Curie temperature and multiferroics. Based on density functional theory calculations, the monolayer VXCl (X = Te, Se, S) and VMSe 2 (M = Al, Ga, In) with tetrahedral coordination structure are predicted to be ferromagnetic semiconductors with high T c and large magnetocrystalline anisotropy. With the monolayer BiCrSe 3 ( T c above 400 K) being treated as the representative sample of octahedral materials, we reveal the disadvantages of two different coordination structures in 2D condition, namely tetrahedral and octahedral coordination, and find that modulation of bond angles is effective and feasible to enhance the magnetic exchange of tetrahedral materials. Moreover, the two series of predicted materials have favorable piezoelectric properties. Our work paves a feasible route for finding new low-dimensional ferromagnetic materials with excellent properties.