材料期刊网

From the high-order perturbation formulae based on the two spin-orbit coupling parameter model, the electron paramagnetic resonance (EPR) parameters D, Deltag(//) (= g(//) - g(s)) and Deltag(perpendicular to) (= g(perpendicular to) - g(s)) for four Co2+ centres in Co2+-doped cubic (3C), hexagonal (2H) and 4H polytype ZnS crystals are studied using the parameters related to the structural data and the optical spectra of the studied systems. From the studies, the defect structures (characterized by the atomic positions, i.e. the relative atomic displacements delta(i) and epsilon(i) of Co2+ and S2- from the ideal positions) for Co2+ in 2H- and 4H-ZnS are obtained (for 3C-ZnS, Co2+ in the regular cubic position). The EPR parameters of various Co2+ centres in 3C-, 2H- and 4H-ZnS are also reasonably explained.