Registration and nucleation of the Ag/Si(111)(√3×√3)<i>R</i>30° structure by scanning tunneling microscopy

Abstract

Scanning tunneling microscope images showing the lateral registration of the Ag/Si(111)(\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{} structure relative to the Si(111)7\ifmmode\times\else\texttimes\fi{}7 structure demonstrate that protrusions are observed at threefold hollow sites. These protrusions can thus be associated with Ag atoms in the honeycomb structure but not with Si atoms in the embedded trimer structure. Images of domain boundaries and steps also suggest that the top double layer of Si is intact, in disagreement with another recent model.