Hybrid functional study of structural, electronic and magnetic properties of S-doped ZnO with and without neutral vacancy

The structural and electronic properties of S-doped ZnO are investigated by density functional theory (DFT) and empirical pseudopotential method (EPM). Using the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional with an adjusted mixing coefficient α, we obtain a good agreement on lattice parameters and band gap energy with the available experimental data. We have also investigate the Zn-vacancy effects on the electronic and magnetic properties of S-doped ZnO. Our calculations demonstrate that S impurity prefers to be close to the cation vacancy in the apical position. The magnetic analysis with the HSE functional shows a triplet state character with a total magnetic moment of 1.81 μB, which is mainly arises from the p-orbitals of the atoms around the Zn-vacancy (15% from S, 12% from Zn and 73% from O-atoms). The substitution of S by an isovalent atom decreases the total magnetic moments of the system and weakens the local triplet state without destroying it.