Epitaxial Graphene Nanoribbons on Bunched Steps of a 6H-SiC(0001)   Substrate: Aromatic Ring Pattern and Van Hove Singularities
  We report scanning tunneling microscopy and spectroscopy investigation of graphene nanoribbons grown on an array of bunched steps of a 6H-SiC(0001) substrate. Our scanning tunneling microscopy images of a graphene nanoribbons on a step terrace feature a (sqrt(3)x sqrt(3))R30{\deg} pattern of aromatic rings which define our armchair nanoribbons. This is in agreement to a simulation based on density functional theory. As another signature of the one-dimensional electronic structure, in the corresponding scanning tunneling spectroscopy spectra we find well developed, sharp Van Hove singularities. 
M. Ridene (1), T. Wassmann (2), E. Pallecchi (1), G. Rodary (1), J. C.   Girard (1) and A. Ouerghi1 ((1) CNRS- Laboratoire d...
cond-mat.mes-hall