Various mechanisms of Si diffusion in GaAs were investigated by using first-principles molecular dynamics methods. It was found that the predominant mechanism involved the motion of negatively charged SiIII-VIII pairs via second-nearest neighbor jumps. This mechanism explained the ability of Si to disorder superlattices (regardless of whether it was introduced during growth or was in-diffused later), and the suppression of interdiffusion by compensation doping. The calculated activation energies were in very good agreement with experimental data.

B.Chen, Q.M.Zhang, J.Bernholc: Physical Review B, 1994, 49[4], 2985-8