First principles calculations of structural, electronic, magnetic and optical properties of Gd doped and Gd, Mn co-doped zinc blende CdS

Abstract

In this work, we studied the magnetic stability, electronic and optical properties of Gd doped CdS and (Gd, Mn) co-doped CdS, in a zinc blend structure, using first-principles calculations based on the full-potential linearized augmented plane wave method (FP-LAPW) with the GGA + U approximation. The lattice parameter increases by Gd doping and decreases by (Gd, Mn) co-doping. The calculations of the differences in total energies ΔE prove that the CdS: Gd is stable in the antiferromagnetic state (AFM). While, the co-doped system CdS: (Gd, Mn) is stable in the ferromagnetic states (FM). The CdS: (Gd, Mn) has an interesting magnetic moment compared to the CdS: Gd. The total densities of states show the metallic character of the CdS: Gd and the half-metallic character of CdS: (Gd, Mn). The real and imaginary parts of the dielectric function, the absorption coefficient, and the refractive index are calculated. Both systems have a significant redshift and have a strong light absorption in the visible and UV regions. Co-doping CdS by Gd and Mn gives interesting results compared to the CdS: Gd. These make CdS: (Gd, Mn) an important material for different applications. This work provides the possibility to fabricate new optoelectronic and spintronic devices.