Utilizing density functional theory, we assess the propagation of interactions between Pb layers intercalated underneath graphene supported on SiC(0001) and Pb atoms adsorbed on top of graphene. Rather than just assessing the adsorption energy at the strongest binding site for the Pb adatom, we map out the entire potential energy surface (PES) for a Pb adatom on these surfaces. As expected, the propagation of Pb-Pb interactions is somewhat stronger through just one layer versus two layers of graphene. We find that for an intercalated Pb layer resembling a hexagonal close-packed Pb(111) layer, the PES does not reflect the periodicity of Pb(111), but rather that of graphene (for either one or two layers of graphene). This disfavors strict remote epitaxy where the intercalated Pb layer directs the formation of an in-registry epitaxial Pb(111) overlayer or thin film. However, this does not exclude the possibility that intercalated and overlayer Pb(111) can be in-registry due to interactions of each with the same graphene layer(s). We discuss the formation of Pb(111)-like islands and thin films by Pb deposition on SiC-supported graphene for cases with and without intercalated Pb. Analysis is based on our assessment of the dependence on Pb intercalation of the PES and of the surface diffusion barriers for adsorbed Pb, and also an assessment of the strength of attractive interactions between Pb adatoms, which control Pb thin film nucleation and growth.

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• Nucleation on surfaces
• Surface & interfacial phenomena
• Surface diffusion
• Density functional theory