材料期刊网

The axial Ti2+ center in a nearly wholly cubic ZnS crystal is assigned to the Ti2+ ion on the hexagonal site of wurtzite structure caused by stacking faults. On the ground of the assignment, the EPR parameters (zero-field splitting D, g factor g(parallel to) and g-anisotropy Delta g = g(parallel to) - g(perpendicular to)) of the axial Ti2+ center are calculated from the high-order perturbation formulas based on the cluster approach for the EPR parameters of 3d(2) ion in trigonal symmetry. From the calculations, the local atom-position parameter u(loc) (which is different from the corresponding parameter u in the host wurtzite structure) and hence the defect structure of the Ti" center are estimated. The results (the calculated EPR parameters and the defect structure) are discussed. (c) 2004 Elsevier B.V. All rights reserved.