Intercalation of a 2-dimensional graphite film on iridium and rhenium by Ag atoms

We have studied Ag adsorption on two-dimensional graphite films on metal surfaces (2DGF) using high resolution Auger spectroscopy. It was rather surprising for us to find out that Ag atoms DO NOT intercalate 2DGF on (111)Ir: up to T=1050K they reside above the graphite layer and at higher temperatures desorb from the surface, but do not penetrate under 2DGF. A similar effect was obtained on metals with other natures and surface crystal structure: on 2DGF on (1010)Re. All other atoms previously studied by us do intercalate 2DGF either under direct deposition on it or by annealing of thick film deposited on 2DGF at room temperature.