Muon level-crossing resonance and muon spin-rotation measurements of heavily Si- or Te-doped n-type material showed that most of the positive muons which were implanted at room temperature formed an isolated diamagnetic muonium center that was located at a high-symmetry site, with Ga neighbors along <111> directions. The results, together with theoretical considerations, implied that negatively charged muonium was located at, or near to, the tetrahedral interstitial site; with four Ga nearest-neighbor atoms. Apart from zero-point energy differences, the results were expected to represent negatively charged isolated H in GaAs.

K.H.Chow, R.E.Kiefl, W.A.MacFarlane, J.W.Schneider, D.W.Cooke, M.Leon, M.Paciotti, T.L.Estle, B.Hitti, R.L.Lichti, S.F.J.Cox, C.Schwab, E.A.Davis, A.Morrobel-Sosa, L.Zavieh: Physical Review B, 1995, 51[20], 14762-5