Density functional theory studies were performed in order to investigate the mechanisms of self-diffusion. A diffusion pre-factor was found for the vacancy mechanism, within harmonic transition state theory, which was in good agreement with experimental values. However, the activation energy was underestimated by almost 1eV when the PW91 functional was used. A cluster correction procedure was proposed which involved the hybrid B3LYP functional and which led to an activation energy of 3.1eV; in agreement with experiment. The contribution of interstitial and exchange mechanisms was negligible.

Theoretical Studies of Self-Diffusion and Dopant Clustering in Semiconductors. B.P.Uberuaga, G.Henkelman, H.Jónsson, S.T.Dunham, W.Windl, R.Stumpf: Physica Status Solidi B, 2002, 233[1], 24-30