First principles calculations of electronic structure and magnetic properties of Cr-based magnetic semiconductors Al1−xCrxX (X=N, P, As, Sb)

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 Al1−xCrxX (X=N, P, As, Sb) for 0≤x≤0.50.The behaviour of magnetic moment of Al1−xCrxX 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 Al1−xCrxN and becomes weaker in Al1−xCrxSb. The band gap due to the spin down electrons decreases with the increased concentration of Cr in Al1−xCrxX, 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 AlX.

The prototype structures of Cr doped AlX (X=N, P, As, Sb) compounds: (A) zinc blende AlP for x=0, (B) Cr1Al7P8 for x=0.125, (C) Cr1Al3P4 for x=0.25, (D) Cr1Al1P2 for x=0.5.Figure optionsDownload as PowerPoint slide