Elastic displacements and step interactions on metallic surfaces: Grazing-incidence x-ray diffraction and ab initio study of Au(332)

摘要

We have studied the energetics, relaxation, and interactions of steps on the Au(332) vicinal surface using a combination of grazing incidence x-ray diffraction, anisotropic linear elasticity theory, and ab initio density-functional theory. We find that the initial force distribution on a bulk-truncated surface, as well as the resulting pattern of atomic relaxations, can be reproduced excellently by a buried dipole elastic model. The close agreement obtained between experimental and calculated x-ray diffraction profiles allows us to precisely determine the value of the elastic dipole density at the steps. We also use these results to obtain an experimental estimate of the surface stress on an unreconstructed Au(111) facet, T_(Au(111))=2.3 ± 0.4 Nm~(-1), and the value of the step-step elastic interaction energy A = 950±150 meV A.