Figure 5

Density Functional Theory explanation of the variable interaction of graphene grown on the PtRu surface alloy.

(a) 2D plot of the simulated moiré cell of GR on the PtRu surface alloy, at various Pt concentrations. The colour scale indicates the C-metal distance. The first layer atoms of the substrate are shown superimposed, with the Pt atoms highlighted in a white shade. (b) Simulated difference map (top and side views) of the charge density of graphene on Ru(0001) and PtRu/Ru(0001), with respect to a completely decoupled GR layer on Ru(0001). Red and blue isosurfaces indicate charge accumulation and depletion regions, corresponding to an electron concentration of ±0.023 e Å⁻³, respectively. Side views: 2D projections of the charge difference map along the plane P normal to the surface plane. (c) DFT-simulated C 1s core level spectra of GR on the Ru and PtRu surfaces and their deconvolution into strongly (S) and weakly (W) interacting GR components.