Gold intercalation of different 6H-SiC(0001) surface reconstructions

We report on in situ investigation of Au intercalation of different zero-layer graphene surface reconstructions of 6H-SiC(0001): (3×3)R30∘+(63×63)R30∘, (63×63)R30∘+(5×5)R0∘, (63×63)R30∘+(5×5)R0∘+Gr. We show that the most appropriate reconstruction for graphene formation via Au intercalation is a one with some fraction of initial graphene monolayer. A well-ordered epitaxial Au(111) islands on the zero-layer graphene were revealed with the same crystallographic orientation as the SiC surface. Ab initio calculations approve that the value of Rashba splitting in graphene increases with the density of Au atoms per unit cell and with the reduction of average distance between Au and graphene.