Identification of the Isolated Ga Vacancy in Electron-Irradiated GaP through EPR

Abstract

An $S=\frac{1}{2}$ EPR spectrum is observed in electron-irradiated GaP: Zn with an isotropic $g=2.0130\mathrm{}\pm 0.0015$ and resolved ligand hyperfine splitting from four equivalent $I=\frac{1}{2}$ neighbors. This spectrum is assigned to the isolated Ga vacancy. A molecular-orbital model for ${V_{\mathrm{Ga}}}^{--}$ is consistent with the experimental data. Analysis of the hyperfine parameters reveals some lattice relaxation although the full $T_d$ symmetry is maintained.