Hong Li (RIKEN, Wako-shi, Japan), N. Sahoo (Albany Medical College, Albany NY; SUNY Albany, Albany, NY), T.P. Das (SUNY Albany), R. Scheuermann (RIKEN), K. Nagamine (KEK-MSL, Tsukuba, Japan; RIKEN)
The electronic structure and associated magnetic hyperfine interactions
for the Neutral Vacancy-Associated Hydrogen (Muonium) Atom Center (B. Bech
Nielsen et al., Phys. Rev. Lett. 79, 1507 (1997)), (M.Schefzik et al, Solid
State Commun. 107, 395 (1998)) in Silicon have been investigated using
theHartree-Fock Cluster Procedure combined with many-body effects incorporated
by perturbation methods. The influence of cluster size, size of electronic
basis-set and lattice relaxation due to the presence of both the vacancy
and muonium atom, have been studied. The results provide an explanation
of the axial anisotropy of the hyperfine interaction tensors and the signs
of the isotropic hyperfine constant and dipolar tensor components.
The sizes of the calculated hyperfine tensor components are however
found to be somewhat larger than experiment. Possible sources that could
bridge the differences will be discussed.