Using ab initio density functional theory the configuration space of In clusters in Si up to size 4 was explored. The strongest binding energy corresponds to a cluster containing one In and 3 self-interstitials. Two plausible configurations almost degenerate in energy were found: the <100>I4 model and an alternative which combined two <110> split di-interstitials. The segregation of In to a InI4 cluster was found to capture the dual peak and the low temperature annealing behavior of In.

Impact of the Size 4 Cluster on Low Temperature Indium Diffusion in Silicon. M.M.De Souza, S.Chakravarthi, A.Jain: Journal of Physics - Condensed Matter, 2005, 17[22], S2165-70