Using an extended Einstein relation, we discuss the concentration dependence of the surface diffusion coefficient in clustering systems. We explain the difference between the surface diffusion coefficient measured by microscopic mass transport techniques (terrace-cluster coexistence surface diffusion) compared to coefficients extracted for a simple hopping process (adatom on terrace surface diffusion). For Sn and Ga on Si the adatom on terraces surface diffusion coefficient is shown to be concentration independent. Literature data for surface diffusion of Ag/Ge(111) and O/W(110) show a concentration dependence which is in good agreement with the dependence predicted for the terrace-cluster surface diffusion.
ASJC Scopus subject areas
- Condensed Matter Physics