Contrary to an intuitive expactation a monatomic hexagonal close packed Pb film on Cu(111) shows an "inverse" corrugation, i.e., the Pb atoms in on top adsorption sites appear lowest in scanning tunneling microscopy (STM) images as well as in effective medium theory (EMT) simulations. On small subsurface Cu islands on a Pb(111) substrate, which are also covered by a monatomic Pb film, the corrugation of this film was found to be strongly dependent on the thickness of the Cu island (the thinner the island the larger the corrugation). EMT simulations reproduce this enhanced corrugation qualitatively and thus further confirm the formation of these subsurface Cu islands. On a p(8x1) superstructure of Pb/Cu(110), similarly, the lowest coordinated Pb atoms also show lowest apparent height in STM images.
Part of this work is on display in the IAP/TU Wien STM Gallery (see the Pb on Cu and Cu on Pb pages).
Corresponding author: M. Schmid (schmid).
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