Oxygen-related anisotropic muonium centres in crystalline silicon

Abstract

A new muonium centre, termed Mu_x, with anisotropic hyperfine interaction has been discovered in crystalline silicon in transverse-field muon spin rotation experiments. Its hyperfine tensor is very close to that of bond centred muonium (Mu_BC). The new muonium centre has been observed only in some of the many samples investigated. A correlation between dopant and oxygen concentration in the investigated samples and the observation of Mu_x has been found, which indicates that Mu_x might be related to a oxygen-muoniuni 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.