The spin-Hamiltonian parameters (g factors g||, g┴ and hyperfine structure constants 63A||, 63A┴, 65A||, 65A┴) for Cu2+ ions in the trigonally-distorted tetrahedral sites of ZnO and GaN crystals were calculated from a complete diagonalization (of energy matrix) method based upon a two spin-orbit parameter model for d9 ions in trigonal symmetry. In the method, the Zeeman and hyperfine interaction terms were added to the Hamiltonian in the conventional complete diagonalization of matrix method. The calculated results were in good agreement with the experimental values. The calculated spin-Hamiltonian parameters were also compared with those using the traditional diagonalization method or perturbation method only within the 2T2 term. It appeared that, for exact calculations of spin-Hamiltonian parameters of d9 ions in trigonal tetrahedral clusters in crystals, the present complete diagonalization of matrix method was preferable to the traditional diagonalization method or perturbation method within the 2T2 term. The local structures of Cu2+ centers (which differed from the corresponding structure in the host crystal) in ZnO:Cu2+ and GaN:Cu2+ were obtained from the calculations.

Theoretical Calculations of Spin-Hamiltonian Parameters and Defect Structures for Cu2+ in Trigonally-Distorted Tetrahedral Sites of ZnO and GaN Crystals. Zheng, W.C., He, L., Mei, Y.: Philosophical Magazine, 2009, 89[9], 789-96