Spin-polarized structural, electronic and magnetic properties of diluted magnetic semiconductors Cd 1− xMn xTe in zinc blende phase

Abstract

We have investigated the structural, electronic and magnetic properties of the diluted magnetic semiconductor (DMS) Cd 1− x Mn x Te (for x=0.75 and 1.0) in the zinc blende (B3) phase by employing the ab-initio method. Calculations were performed by using the full potential linearized augmented plane wave plus local orbitals (FP-L/APW+lo) method within the frame work of spin-polarized density functional theory (SP-DFT). The electronic exchange-correlation energy is described by generalized gradient approximation (GGA). We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii, spin-polarized band structures, and total and local densities of states. We estimated the spin-exchange splitting energies Δ x ( d) and Δ x ( pd) produced by the Mn3 d states, and we found that the effective potential for the minority spin is more attractive than that of the majority spin. We determine the s–d exchange constant N 0 α (conduction band) and p–d exchange constant N 0 β (valence band) and these somewhat agree with a typical magneto-optical experiment. The value of calculated magnetic moment per Mn impurity atom is found to be 4.08 μ B for Cd 0.25Mn 0.75Te and 4.09 μ B for Cd 0.0Mn 1.0Te. Moreover, we found that p–d hybridization reduces the local magnetic moment of Mn from its free space charge value of 5.0 μ B and produces small local magnetic moments on the nonmagnetic Cd and Te sites.