The microscopic mechanisms of Zn diffusion in GaAs were investigated by using  ab initio  molecular dynamics techniques. It was found that, among the various proposed mechanisms for Zn diffusion, kick-out by Ga interstitials had the lowest activation energy. The occurrence of Zn in-diffusion generated non-equilibrium group-III interstitials which were bound to Zn by Coulomb forces. The interstitials followed the Zn diffusion front and disordered the superlattice. The calculated activation energies for these processes were in good agreement with experimental data.

C.Wang, Q.M.Zhang, J.Bernholc: Physical Review Letters, 1992, 69[26], 3789-92