Bond-centered muonium (MuBC0) was observed in very heavily doped n-type P-doped material. It exhibited a Curie-like electronic spin susceptibility which led to a giant negative shift in the muon spin precession frequency. At high dopant levels, the MuBC0 hyperfine parameters – as deduced from a model which involved spin exchange with free carriers - were significantly reduced as compared with those in intrinsic material. This indicated that the spin-density distribution of MuBC0 in metallic P-doped material was significantly altered by charge-screening effects.

Novel Behavior of Bond-Centered Muonium in Heavily Doped n-Type Silicon - Curie-Like Spin Susceptibility and Charge Screening K.H.Chow, R.F.Kiefl, B.Hitti, T.L.Estle, R.L.Lichti: Physical Review Letters, 2000, 84[10], 2251-4