First principle study of Mn-doped and vacancy on the magnetism and optical properties of CdS

The generalized gradient approximation method under the framework of spin polarization density functional theory combined with Hubbard U correction is used to study the effects of Mn-doping and vacancy on the magnetic properties and optical properties of CdS. The results show that the system is antiferromagnetic when the two Mn atoms are doped nearest-neighbor, the system has no magnetism when S vacancy. The system has ferromagnetism when Cd vacancy or two Mn-doping next nearest-neighbor, and they have a Curie temperature above room-temperature. The system is also ferromagnetic when doping and vacancy coexist. The magnetic source is the exchange between Mn-3d electrons or the electronic exchange of Mn-3d and unpaired 3s (3p) orbitals of S atoms near the vacancy. Mn single-doped absorption is strong in the visible range, and two Mn-doped systems have better transmission. The calculation of the formation energy shows that the two Mn-doped system is easy to form, but the Cd (S) vacancy are not easy to form experimentally.