Self-interstitial clustering in crystalline silicon

We have proposed a novel model of a self-interstitial defect in crystalline Si. It contains four Si interstitials and has the structural features as follows: All silicon atoms are four coordinated, in contrast to previously proposed models; the defect is characterized by five-, six-, and seven-membered atomic rings. The total energy, the relaxed atomic configuration, and the electronic structure of the defect have been determined using the transferable semiempirical tight binding method.