The perturbed γ-γ angular correlation method was used to study isolated 111In probe atoms on vicinal Cu(111) surfaces. The properties of the observed electric field gradients, and the annealing behavior, suggested the existence of In as step-adatoms at temperatures of up to 140K. Above this temperature, these adatoms changed into substitutional step atoms. At 220K, the In probes finally began to diffuse into substitutional terrace sites. Desorption and diffusion into the bulk were also detected. The activation energies were estimated from the thermal conversion behavior between the various sites.

T.Klas, R.Fink, G.Krausch, R.Platzer, J.Voigt, R.Wesche, G.Schatz: Europhysics Letters, 1988, 7[2], 151-7