Terrace-width distributions on vicinal Ag(110): evidence of oscillatory interactions
Journal
Surface Science
Journal Volume
307-309
Journal Issue
PART B
Pages
747-754
Date Issued
1994
Author(s)
Abstract
The distribution of terrace widths on vicinal Ag(110) surfaces is measured with scanning tunneling microscopy as a function of mean terrace width 〈l〉 and interpreted in terms of a step-step interaction potential. As previously observed on vicinal Cu(100) surfaces, but in contrast to reports involving semiconductor surfaces, the distribution does not scale simply with 〈l〉. For vicinal Ag(110) surfaces with 〈l〉 = 22 A ̊, the distribution resembles that expected for noninteracting steps. For 〈l〉 = 30 A ̊, the distribution narrows significantly, suggesting repulsive interactions. For 〈l〉 = 40 A ̊, the distribution has a form expected for attractive interactions. The absence of simple scaling of this distribution reveals that the decay of step-step interactions is more complicated than the l-2 behavior expected for elastic or dipolar repulsions. A nonmonotonic potential is found to reproduce the observed terrace-width distributions, as demonstrated with Monte Carlo simulations of a terrace-step-kink model. According to this trial potential, step interactions are dominated by a repulsive l-2 term at short l and by an RKKY-like oscillatory term at longer l. The form of the latter term is reminiscent of indirect interactions between adsorbates. © 1994.
SDGs
Type
journal article