Electronic Structure of Transition Metal Impurities in Zinc Sulphide

The Green's function method is used to calculate the electronic states associated with the following neutral substitutional transition‐metal impurities in zinc sulphide:scandium, titanium, vanadium, manganese, iron, cobalt, nickel. Clusters of 17 atoms in a tetrahedral configuration are used to simulate the bulk and the locally perturbed crystal. The results indicate that the impurities studied yield acceptor energy levels deep in the crystal fundamental band gap. The role played by the metal d states in the formation of the impurity centres is disscussed and compared with available experimental data.