First-principles calculations agreed with field ion microscopy data to the effect that the barrier to substitutional diffusion of a Pt atom on (001)Pt varied linearly with the external electric field, and changed by about 0.1eV per V/Å. It increased for fields that were oriented so as to push electrons into the surface. However, a computed hopping barrier - which remained more than 0.5eV higher than that for substitution - contradicted the suggestion that a change in field ion microscopy site visitation, at fields of 1.5 to 2V/Å and temperatures of 265 to 284K, could be attributed to the onset of hopping.

Surface-Diffusion Mechanism Versus Electric Field - Pt/Pt(001). P.J.Feibelman: Physical Review B, 2001, 64[12], 125403 (6pp)