A photo-stimulated electron paramagnetic resonance spectrum, which was observed by means of conventional and thermally detected electron paramagnetic resonance techniques, was attributed to the neutral charge-state of the Mn acceptor. The photo-stimulated spectrum exhibited the characteristics of a tetragonally distorted center with an integer spin, and was attributed to a 3d4 ion (MnGa3+) on strain-stabilized sites of tetragonal symmetry (due to strong Jahn-Teller coupling of the 5T2 ground state). It was concluded that the electron paramagnetic resonance spectra confirmed that the neutral charge state of the Mn acceptor was a 3d4 ion, MnGa3+(A0); contrary to the situation in GaAs or InP, with a [Mn2+,hole] complex.

J.Kreissl, W.Ulrici, M.El-Metoui, A.M.Vasson, A.Vasson, A.Gavaix: Materials Science Forum, 1995, 196-201, 725-30