Analysis of prefactors for interlayer diffusion of Ag/Ag(111) - art. no. 035418

摘要

The parameters nu(s)u(t) and DeltaE(s) for Ag/Ag(111) describing the interlayer diffusion probability p=(nu(s)u(t)e(-(DeltaE s/kT))) have been measured by different methods. Different results are obtained for the prefactor ratio nu(s)u(t), with nu(s)u(t)>1 extracted at low temperatures T<150 K while nu(s)u(t)similar to1 is extracted at higher temperatures T=300 K. We examine as a possible reason for the discrepancy, the dependence of the step-edge barrier on the type of microscopic site (i.e., kinks vs straight-step sites) or whether long-range interactions play a role. Both factors can lead to non-Arrhenius temperature dependence. In addition we examine the conditions necessary for a steady state to hold in island decay experiments which are used to conclude nu(s)u(t)similar to1 and when such conditions are fulfilled for Ag/Ag(111). [References: 21]