Impurity-Vacancy Complexes in Si and Ge

We examine the electronic and geometrical structure of impurity-vacancy complexes for 11 sp-impurities in Si and Ge, using the pseudopotential plane wave (PPW) and the all-electron Kohn–Korringa–Rostoker (KKR) methods. We find that all impurities of the 5sp and 6sp series prefer the split-vacancy configuration. For Cd and Sn we obtain good agreement of the calculated hyperfine parameters with experimental PAC and EPR data. Impurities of the 3sp and 4sp series form distorted substitutional complexes (except Al, which forms a split complex in Si). This trend strongly correlates with the lattice relaxations of nearest neighbors around the isolated (without vacancy) substitutional impurities.