First principles investigations of optoelectronic and magnetic properties of co-doped zinc sulphide by 3d and 4f elements

In this work, optoelectronic and magnetic properties of Co-doped and (Co, Sm) co-doped ZnS have been studied using the first principles calculation based on density functional theory (DFT) and FP-LAPW method with GGA and GGA + U approximations in zinc blende structure. The lattice parameter will increase by (Co, Sm) co-doping ZnS. The difference in total energy is calculated and confirms the stability of ZnS: Co in ferromagnetic states (FM) and ZnS: (Co, Sm) in antiferromagnetic states (AFM). The total magnetic moment is found to be more interesting by (Co, Sm) co-doping. The band structure, the total density of states (TDOS) and partial density of states (PDOS) show that ZnS: Co has a semiconducting character. While ZnS: (Co, Sm) has half-metallic character behavior with 100% spin polarization at the Fermi level provided by the RE-4f states. Moreover, optical properties such as dielectric functions and absorption coefficients for ZnS: Co and ZnS: (Co, Sm) were also discussed and found to be more interesting in the visible region by (Co, Sm) co-doping. The improved optical and magnetic results indicate that (Co, Sm) co-doped ZnS can be used as a promising candidate for optoelectronic and spintronic devices in the future.