Nucleation and evolution of the Au-induced 5×2 structure on vicinal Si(111)

Abstract

Topographical changes on vicinal Si(111) have been followed as a function of submonolayer Au coverage. Nucleation at step edges leads to subsequent growth of a single-domain overlayer of the Au-induced 5\ifmmode\times\else\texttimes\fi{}2 structure. Phase boundaries between step, 7\ifmmode\times\else\texttimes\fi{}7 and 5\ifmmode\times\else\texttimes\fi{}2 regions have been studied, as well as the detailed structure of the step and 5\ifmmode\times\else\texttimes\fi{}2 regions. Gradual changes in facet angle on the surface occurred, driven by 5\ifmmode\times\else\texttimes\fi{}2 terrace growth. An inhomogeneous coverage of Au was observed, with a pattern extending over distances on the order of micrometers, indicating large-scale surface diffusion of both Au and Si atoms.