Determination of Interlayer Diffusion Parameters for Ag/Ag(111)

It is well known that the Ag/Ag(111) epitaxial system grows three dimensionally because of the existence of a relatively high excess diffusion barrier, $\Delta E_s=0.13\mathrm{eV}$, at the step edges. Several experimental methods have been developed to measure the step edge barrier in this system over a wide coverage range. The probability for an atom to move from a higher to a lower layer depends on both the barrier and the prefactor, so it is important to test whether the prefactors for hopping over a step, ${\nu }_s$, and for hopping on a terrace, ${\nu }_t$, are different. We present the results from several experiments on Ag/Ag(111) to conclude that ${\nu }_s/{\nu }_t{=10\mathrm{}}^{2.0\pm 0.3}$.