A theory was developed for impurity diffusion under equilibrium and non-equilibrium concentrations of point defects. The results of first-principles calculations of several key quantities were combined with the theory and were compared with experimental data. It was found that vacancies and self-interstitials governed the equilibrium diffusion of As. Interstitials tended to predominate. It was also found that the direct-exchange mechanism played only a minor role.

C.S.Nichols, C.G.Van de Walle, S.T.Pantelides: Physical Review Letters, 1989, 62[9], 1049-52