Density functional studies of magneto-optic properties of CdCoS

• Cd1-xCoxS (0≤x≤0.75) is theoretically investigated with GGA+mBJ.
• The material is ferromagnetic and its magnetization increases with Co concentration.
• The compound has wide and direct band gap nature.
• The band gap of the compound varies in visible region, therefore precious for solar cell applications.
• Strong exchange interaction is found between the Co-3d and S-3p states.

Density functional calculations are performed to investigate the structural, electronic, magnetic and optical properties of Cd1−xCoxS (0≤x≤0.75) in cubic zinc-blende structure. Accurate exchange potential modified Becke and Johnson (mBJ) within the FP-FLAPW method has been used in the calculations. Lattice constant of the alloy decreases while band gap first decreased and then increased with increased in Co concentration. The decrease in the band gap of CdS substituted Co 25% is because of the exchange interaction between Co-3d and S-3p state. The ferromagnetic nature of material is due the spin polarization of Co-3d state and the magnetization of the compound is increased with increased in Co concentration. The band gap energy varies mostly in visible region of the electromagnetic spectrum; therefore the material is precious for solar cell application. The optical properties like dielectric constant, index of refraction and reflectivity are also calculated.