Spin-polarized electronic structure and magnetic properties of Ge_(1-x)TM_xTe (TM = Mn, Fe)

摘要

We have investigated the structural, electronic and magnetic properties for Ge_(1-x)TM_xTe (TM = Mn, Fe) in the rock-salt (RS) structure for (0≤x≤1). The calculations were performed using the full potential linearized augmented plane wave plus local orbitals method (FP-LAPW+lo) within the frame work of the density functional theory and the generalized gradient approximation (GGA). Structural properties are determined from the total energy calculations and results are given for the lattice parameters, bulk moduli and spin magnetic moments. The analysis of band structures and density of states reveals that for x=0.125 and x=0.25, GeMnTe is a narrow gap semiconductor and GeFeTe is a half metal while for x=0.5 and x=0.75 both alloys present a metallic character. Furthermore, we predict the values of spin exchange splitting energies Δ_x(d) and Δ_x(pd) and exchange constants N_(0α) and N_(0β) produced by the 3d Mn and 3d Fe states.