Structural and electronic inhomogeneity for graphene grown on the C-face of SiC: Insights from ab initio calculations

The graphitization of the SiC(0 0 0 1¯) plane, commonly referred to as the C-face of SiC, takes place through the sublimation and reorganization of surface atoms upon high-temperature annealing. Often, such reorganization gives rise to ordered atomic reconstructions over the ideally flat (0 0 0 1¯) plane. In this article, we use the density functional theory to model graphene/SiC(0 0 0 1¯) interfaces with an (1 × 1), (2 × 2) and (3 × 3) SiC periodicity. Our results indicate that the interface geometry can be crucial for both the stability and the electronic characteristics of the first graphitic layer, revealing a complex scenario of binding, doping and electronic correlations. We argue that the presence of more than one interface geometry at different areas of the same sample could be a reason for structural inhomogeneity and n- to p-type transitions.