Theoretical investigations of the EPR parameters and local structure for Cu2+in BeO

The electron paramagnetic resonance (EPR) parameters (the anisotropic g factors, the hyperfine structure parameters and the quadrupole coupling constant Q) and local structure for Cu2+ in BeO are theoretically investigated from the perturbation formulas of these parameters for a 3d9 ion under trigonally distorted tetrahedra. The ligand orbital and spin-orbit coupling contributions are included in the basis of the cluster approach, in view of the strong covalency of the [CuO4]6- cluster. From the calculations, the impurity Cu2+ is suggested not to occupy exactly the ideal Be2+ site but to suffer a slight inward displacement (0.024) toward the ligand triangle along the C3 axis. The theoretical EPR parameters show good agreement with the experimental data.