title: Potential energy landscape for hot electrons in periodically nanostructured graphene.
abstract: We explore the spatial variations of the unoccupied electronic states of graphene epitaxially grown on Ru(0001) and observed three unexpected features: the first graphene image state is split in energy; unlike all other image states, the split state does not follow the local work function modulation, and a new interfacial state at +3  eV appears on some areas of the surface. First-principles calculations explain the observations and permit us to conclude that the system behaves as a self-organized periodic array of quantum dots.
authors.affiliation: Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Borca
authors.forename: S
authors.initials: S
authors.lastname: Barja
authors.forename: M
authors.initials: M
authors.lastname: Garnica
authors.forename: D
authors.initials: D
authors.lastname: Sánchez-Portal
authors.forename: V M
authors.initials: VM
authors.lastname: Silkin
authors.forename: E V
authors.initials: EV
authors.lastname: Chulkov
authors.forename: C F
authors.initials: CF
authors.lastname: Hermanns
authors.forename: J J
authors.initials: JJ
authors.lastname: Hinarejos
authors.forename: A L
authors.initials: AL
authors.lastname: Vázquez de Parga
authors.forename: A
authors.initials: A
authors.lastname: Arnau
authors.forename: P M
authors.initials: PM
authors.lastname: Echenique
authors.forename: R
authors.initials: R
authors.lastname: Miranda