PGa-antisite-related neutral complex defect in GaP studied with optically detected magnetic resonance

A triplet ($S=1\mathrm{}$) spectrum for a deep ${\mathrm{P}}_{\mathrm{Ga}}$-antisite-related complex defect in (Cu,Li)-codoped GaP has been studied with optical detection of magnetic resonance. The defect has a $〈110〉$ orientation, and a hyperfine interaction in agreement with ${\mathrm{P}}_{\mathrm{Ga}}$ is clearly resolved, although the magnitude of the $\overleftrightarrow{A}$ tensor is considerably reduced compared to the isolated ${\mathrm{P}}_{\mathrm{Ga}}$ defect. The electronic structure of the defect is consistent with a strongly localized electron-hole pair, recombining radiatively at a neutral defect, suggested to be a ${\mathrm{P}}_{\mathrm{Ga}}$-${\mathrm{Cu}}_{\mathrm{Ga}}$ pair. The anisotropic behavior of the $\overleftrightarrow{g}$ tensor (and in part the $\overleftrightarrow{D}$ tensor) is explained as mainly due to a residual spin-orbit interaction of the bound hole.