Oxygen-related anisotropic muonium centres in crystalline silicon

A new muonium centre, termed Mu(X), with anisotropic hyperfine interaction has been discovered in crystalline silicon in transverse-field muon spin ro tation experiments. Its hyperfine tensor is very close to that of bond cent red muonium (Mu(BC)) The new muonium centre has been observed only in some of the many samples investigated. A correlation between dopant and oxygen c oncentration in the investigated samples and the observation of Mu(X) has b een found, which indicates that Mu(X) might be related to a oxygen-muonium centre. According to the hyperfine tensor of Mu(X) the new muonium species is attributed to an oxygen-Mu(BC) complex. The Mu(X) signal is affected by applied electrostatic fields in contrast with the signal of all other known muon species.