Optically detected magnetic resonance in oxygen-doped GaP

New results from optically detected magnetic resonance (ODMR) studies of oxygen-doped GaP are reported. We show that the previous attribution of a triplet resonance spectrum with a characteristic Ga-related four-line hyperfine splitting to the 841-meV oxygen-donor capture emission is incorrect. Careful measurements of the spectral dependence of the ODMR signals show that the triplet spectrum comes from a different emission, probably related to a ${\mathrm{Ga}}_{\mathrm{i}}$ (gallium interstitial) complex, superimposed on the O-related 1.4-eV band. An Auger-type intersite energy-transfer process from the ${\mathrm{Ga}}_{\mathrm{i}}$ complex to the deep neutral O donor explains the ODMR data.