First-principles calculations were made of the diffusion of Cu adatoms on (001) surfaces. A hopping mechanism with a calculated energy barrier of 0.69eV was found to be favored over an exchange mechanism with an activation energy of 0.97eV. It was found, from geometrical relaxations, that adatoms were appreciably attracted to the surface and pushed away nearest-neighbor atoms in the surface. The lateral relaxations of atoms in the surface were larger than the vertical ones.

C.Lee, G.T.Barkema, M.Breeman, A.Pasquarello, R.Car: Surface Science Letters, 1994, 306[3], 575-8