SiCCSiantisite pairs in SiC identified as paramagnetic defects with strongly anisotropic orbital quenching

Abstract

The nearest-neighbor antisite pair defects in 4H-SiC, 6H-SiC, and 3C-SiC single crystals have been identified using electron paramagnetic resonance spectroscopy in combination with a nonperturbative ab initio scheme for the electronic $g$ tensor. Based on the theoretical predictions, the positively charged defect has been found experimentally also in the cubic 3C-SiC polytype where it is characterized by spin 1/2 and highly anisotropic $g$ values of ${g}_{xx}=2.0030$, ${g}_{yy}=2.0241$, and ${g}_{zz}=2.0390$ within ${\text{C}}_{1h}$ symmetry. The exceptional large $g$ values are explained by details of the spin-orbit coupling causing a strongly anisotropic quenching of the orbital angular momentum of the $p$-like unpaired electron.