Study of Half Metallic Ferromagnetism and Optical Properties of Mn-Doped CdS

The spin-polarized electronic band structures, density of states and optical and magnetic properties of dilute magnetic semiconductors (DMSs) Cd 1− x Mn x S with 6.25%, 12.5% and 25% concentrations of Mn have been studied by using ab initio calculations. The electronic band structures show half metallic ferromagnetic (HMF) behaviour with direct band gap at Γ symmetry point. The calculated values of band gaps are 0.8 eV, 0.99 eV, 1.3 eV and 1.5 eV for CdS, Cd 0 . 9375 Mn 0.0625 S, Cd 0 . 875 Mn 0.1250 S and Cd 0 . 75 Mn 0.25 S, respectively. The energy gap of CdS was found to increase by doping with transition metal impurity. The addition of the dopant atoms in CdS turns it into a p -type semiconductor. This half metallic character makes these compounds a potential candidate for spintronics applications. In optical properties, the role of Mn concentration on the absorption coefficient, optical conductivity, refractive index, extinction coefficient and dielectric function has been investigated. The total magnetic moment is found approximately 5.000 μB per dopant atom for Cd 1− x Mn x S ( x = 6.25%, 12.5% and 25%). This value indicates that every Mn impurity adds no hole carriers to the perfect CdS crystal.