Bond-centered muonium in diamond: Resolved nuclear hyperfine structure

Abstract

The nuclear hyperfine structure of bond-centered muonium in $^{13}\mathrm{C}$ enriched diamond has been resolved using time-differential transverse-field muon spin rotation. The measured nearest-neighbor $^{13}\mathrm{C}$ hyperfine parameters are compared to theoretical values from a recent ab initio Hartree-Fock type cluster calculation. The ratios of the measured $^{13}\mathrm{C}$ hyperfine parameters and free atom values indicate that 92% of the unpaired electron spin density resides on the two nearest-neighbor atoms, in marked contrast with the situation for the analogous muonium center in Si.