Electronic Structure and Ferromagnetic Properties of Doped Calcium Sulfide CaTMxS (TM V, Cr and Co)
Abstract
The electronic structure and magnetic properties of diluted CaTMxS (TMV, Cr and Co) in the rocksalt structure at concentrations , 0.125 and 0.25 were studied using the full-potential linearized augmented plane wave approximation of the density functional theory with the Wu-Cohen generalized gradient approximation (WC-GGA) and the Tran–Blaha-modified Becke–Johnson (TB-mBJ) potential. Features such as lattice constant, bulk modulus, spin-polarized band structures, total and local densities of states and magnetic properties have been computed. The electronic structure show that Ca(V, Cr)xS at all the studied concentrations and the diluted CaCoxS with compounds are half-metallic ferromagnets with spin polarization of 100%. The calculated total magnetic moments for CaVxS and CaCoxS show the same integer value of 3 per formula unit and CaCrxS exhibit a total magnetic moment of 4, which confirm the half-metallic behavior of these compounds. We also calculated the values of the band edge spin splitting of the valence and conduction bands and the exchange constants. We have found that the ferromagnetic state is stable by the p-d exchange associated with the double-exchange mechanism. The diluted Ca(V,Cr,Co)xS are found to be new promising candidates for spintronic applications.