First principles calculations of electronic structure and magnetic properties of Cr-based magnetic semiconductors Al 1−xCr xX ( X=N, P, As, Sb)

Abstract

First principles calculations based on the density functional theory (DFT) within the local spin density approximation are performed to investigate the electronic structure and magnetic properties of Cr-based zinc blende diluted magnetic semiconductors Al 1− x Cr xX ( X=N, P, As, Sb) for 0≤ x≤0.50.The behaviour of magnetic moment of Al 1− x Cr xX at each Cr site as well as the change in the band gap value due to spin down electrons has been studied by increasing the concentration of Cr atom and through changing X from N to Sb. Furthermore, the role of p–d hybridization is analyzed in the electronic band structure and exchange splitting of d-dominated bands. The interaction strength is stronger in Al 1− x Cr x N and becomes weaker in Al 1− x Cr x Sb. The band gap due to the spin down electrons decreases with the increased concentration of Cr in Al 1− x Cr xX , and as one moves down along the isoelectronic series in the group V from N to Sb. Our calculations also verify the half-metallic ferromagnetic character in Cr doped Al X.