Effect of gold intercalation on the electronic structure of graphene on Co–Si/SiC(0001)

Graphene grown on an ultrathin CoSi/CoSi$_2$ silicide layer atop a SiC(0001) substrate and intercalated by Au was studied. Intercalation of Au was found to occur at a temperature of 500$^\circ$C, and it is accompanied by the formation of gold silicide under graphene with a stoichiometry close to Au$_2$Si. The study of the electronic structure of the system in the region of the $\bar{K}$ point of the surface Brillouin zone revealed the quasi-freestanding character of graphene with a linear spectrum of $\pi$ states and a Dirac point near the Fermi level. Photoelectron microscopy revealed the homogeneity of the work function along the surface of the sample on a micrometer scale.