Stability of Si-interstitial defects: From point to extended defects

Trends in the growth of extended interstitial defects are extracted from ex tensive tight-binding and ab inito local density approximation simulations. With an increasing number of interstitials, the stable defect shape evolve s from compact to chainlike to rodlike. The rodlike {311} defect, formed fr om (011) interstitial chains, is stabilized as it grows, elongating in the chain direction. Accurate parametrization of the defect-formation energy on the number of interstitials and interstitial chains, together with the ani sotropy of the interstitial capture radius. enables macroscopic defect-grow th simulations.PACS numbers: 61.72.Cc, 61.72.Ji, 71.55.-i.