Electron paramagnetic resonance parameters for variousV3+centers in4H- and6H−SiCcrystals

Abstract

In this paper, the complete high-order perturbation formulas of electron-paramagnetic-resonance (EPR) parameters (zero-field splittings and g factors) for ${3d}^{2}$ ion in trigonal tetrahedral clusters have been derived from a cluster approach. In these formulas, not only the contribution due to crystal-field mechanism, but also the contributions due to charge-transfer mechanism (which is neglected in the crystal-field theory) are included. From these formulas, the g shifts $\ensuremath{\Delta}{g}_{\ensuremath{\parallel}}{(=g}_{\ensuremath{\parallel}}\ensuremath{-}{g}_{e}),$ $\ensuremath{\Delta}{g}_{\ensuremath{\perp}}{(=g}_{\ensuremath{\perp}}\ensuremath{-}{g}_{e})$ and the zero-field splittings D for various ${\mathrm{V}}^{3+}$ centers in $4H$- and $6H\ensuremath{-}\mathrm{SiC}$ crystals are reasonably explained. It is found that in the studies of EPR parameters for ${3d}^{2}$ ions (particularly, in the case of ions having high valence state) in strong covalency crystals, both the contribution due to crystal-field mechanism and that due to charge-transfer mechanism should be taken into account.