A theoretical study was made of self-interstitial defects by using the local density approximation, the generalized gradient approximation, and fixed-node diffusion quantum Monte Carlo methods. The formation energies of the most stable interstitial defects were equal to about 3.3eV according to the local density approximation, to 3.8eV according to the generalized gradient approximation and to 4.9eV according to the quantum Monte Carlo technique. The latter results indicated a value of about 5eV for the formation-plus-migration energy of the self-interstitial contribution to self-diffusion. This was consistent with the experimental data, and illustrated the importance of properly treating electron correlations when studying such systems.

Calculations of Silicon Self-Interstitial Defects W.K.Leung, R.J.Needs, G.Rajagopal, S.Itoh, S.Ihara: Physical Review Letters, 1999, 83[12], 2351-4