Self-diffusion on copper surfaces

The diffusion paths and activation energies of a Cu adatom on Cu(100), Cu(111), and Cu(110) are studied using the effective-medium theory to calculate the energetics. For the (100) and (110) faces, diffusion via an exchange mechanism is found to be important. The transition state for these paths is stabilized by a direct covalent interaction as proposed by Feibelman. On the (111) face and for diffusion along the close-packed rows on the (110) surface, a simple hopping mechanism is found to be most favorable.