Investigations of the electron paramagnetic resonance parameters and defect structures for Cu2+ ions in BeO crystal with trigonally distorted tetrahedral symmetry

The electron paramagnetic resonance(EPR) parameters (g factors g_i and hyperfine structure constants A_i, where i = x, z) for Cu²⁺ ions embedded in beryllium oxide (BeO) crystal at Be²⁺ sites with C_3v local symmetry have been calculated by the complete diagonalization method (CDM) and high-order perturbation theory method (PTM). The calculated results from the two methods are in reasonable agreement with the observed data available. The defect structural data of the trigonal Cu²⁺ center in beryllium oxide are determined from the calculations and analyses. The calculated results show that the Be²⁺ ions are replaced by Cu²⁺ ions in BeO crystal and the ligands undergo outward movement.