The effects of the super-cell approximation in first-principles calculations for isolated, charged point defects in semiconductors and insulators were studied. The convergence of the Coulomb energy with respect to the super-cell size was investigated. Quantitative numerical results for the standard uniform compensating charge and the newly proposed localized compensating charge scheme were presented for a prototypical defect, the doubly-positive Si self-interstitial.

Charged Point Defects in Semiconductors and the Supercell Approximation. J.Lento, J.L.Mozos, R.M.Nieminen: Journal of Physics - Condensed Matter, 2002, 14[10], 2637-45