A semi-empirical many-body interatomic potential for Al, which had been obtained within the second-moment approximation to the tight-binding model, was used – together with molecular dynamics simulations - to study the self-diffusion of single adatoms on the (100) and (111) surfaces. The diffusion coefficient was calculated for the case of the Al/Al(100) system, and was found to exhibit Arrhenius behavior. The migration energies and pre-exponential factors for both hopping and exchange mechanisms were also determined. It was found that the hopping mechanism predominated at temperatures below 800K. The results for the migration energy of Al on Al(111) were in good agreement with recent experimental data. However, there was a marked discrepancy in the case of the pre-exponential factor. The temperature dependence of the relaxation of adatoms was also obtained for the (100) and (111) surfaces. The (111) surface was found to exhibit a stronger temperature dependence.

Self-Diffusion on Al(100) and Al(111) Surfaces by Molecular-Dynamics Simulation. N.I.Papanicolaou, V.C.Papathanakos, D.G.Papageorgiou: Physica B, 2001, 296[1-3], 259-63