Evolution of energetics and bonding of compact self-interstitial clusters in Si

Abstract

The growth of self-interstitial clusters in crystalline Si isinvestigated by semi-empirical tight-binding moleculardynamics. The equilibrium configuration of each n-interstitial cluster(n = 2 − 11) has been obtained by adding one more dumbbell defect to thepreviously relaxed (n − 1) SI cluster in the series. We find an evolutionary path from compact (n < 5) to elongated (n ⩾ 5) clusters.We relate the shape evolution of clusters to the changes in their atomic coordination and bonding properties, using first principles structure calculations and a topological analysis of their associated electron densities.