Theoretical investigations of EPR parameters and local structure of single erbium center in hexagonal GaN layers

In this paper, obtained results from free-ion and the crystal-field analysis of the Er3+ single center energy levels in hexagonal GaN are used to investigate theoretically the EPR parameters. The EPR g-factors g// and g⊥ and hyperfine structure constants A// and A⊥ are investigated using the perturbation formulas. The lowest Kramerʹs doublet is found to be Γ4 for Er3+ ion in trigonal site symmetry. The admixture of different states is induced. The calculated EPR parameters are in a good agreement with the experimental values.