Theoretical investigations of the local structures and the g factors for 3d9 ions in CdS

Abstract

The local structures and the g factors g // and g ⊥ for the isoelectronic 3d9 ions Cu2+ and Ni+ in CdS are theoretically investigated from the perturbation formulas of these parameters for a 3d9 ion under trigonally distorted tetrahedral environments. In consideration of significant covalency of the [MS4] combinations (M = Cu and Ni), the ligand orbital and spin–orbit coupling contributions are taken into account using the cluster approach. Based on the studies, the substitutional impurity Cu2+ (or Ni+) on Cd2+ site is found to undergo a small inward displacement 0.026 A (or a slight outward shift 0.017 A) towards (or away from) the ligand triangle along C 3 axis. The theoretical g factors for both ions based on the above impurity displacements are in good agreement with the experimental data.