Complete high-order perturbation formulae for the electron paramagnetic resonance parameters (zero-field splittings and g-factors) of the 3d2 ion in trigonal tetrahedral clusters were deduced by using a cluster approach. In these formulae, not only the contribution due to crystal-field mechanisms, but also the contributions due to charge-transfer mechanisms (which were neglected in crystal-field theory) were included. Using these formulae, the g-shifts Δg|| (= g||–ge), Δg (= g–ge) and the zero-field splittings for various V3+ centers in 4H- and 6H-SiC crystals could be reasonably explained. It was found that, in studies of the electron paramagnetic resonance parameters of 3d2 ions (particularly in the case of ions having a high valence state) in strongly covalent crystals, both the contribution due to crystal-field mechanisms and that due to charge-transfer mechanisms should be taken into account.

Electron Paramagnetic Resonance Parameters for Various V3+ Centers in 4H- and 6H-SiC Crystals. W.C.Zheng, S.Y.Wu, M.Gong, J.Zi: Physical Review B, 2002, 66[24], 245206 (6pp)