Shape, width, and replicas of π bands of single-layer graphene grown on Si-terminated vicinal SiC(0001)

Massless pi bands of graphene grown on a SiC(0001) substrate can be affected by the scattering at the boundaries and the interface superstructure. We investigated the pi band structure and width of the single-and double-layer graphenes grown on a vicinal SiC(0001) substrate using angle-resolved photoemission spectroscopy. The pi electron scattering at the substrate steps makes the spectrum width anisotropic but no difference occurs in the pi band shape. Quasi-2x2 replicas of the pi band due to the interface 6 root 3x6 root 3R30 degrees superstructure were observed in the single-layer graphene while they were absent in the double-layer graphene.