First-principles pseudopotential calculations were used to estimate the formation energies, of point defects in crystalline material, by using a super-cell of 64 atoms. In the case of the self-interstitial defect, a weak bond was formed between 2 defect Si atoms. No evidence was found for extra bond formation. The formation energies of both defects were comparable: with 3.7eV for the vacancy and 3.25eV for the self-interstitial. The self-interstitial formation energy agreed well with other theoretical results, but the vacancy formation energy was much smaller. Results were also obtained for B substitutional impurities, and the charge density plot indicated an ionic nature for the B-Si bonding.

Ab initio Pseudopotential Calculations of Point Defects and Boron Impurity in Silicon. J.Zhu, L.H.Yang, C.Mailhiot, T.Diaz de la Rubia, G.H.Gilmer: Nuclear Instruments and Methods in Physics Research B, 1995, 102[1-4], 29-32