title: Understanding the origin of band gap formation in graphene on metals: graphene on Cu/Ir(111).
abstract: Understanding the nature of the interaction at the graphene/metal interfaces is the basis for graphene-based electron- and spin-transport devices. Here we investigate the hybridization between graphene- and metal-derived electronic states by studying the changes induced through intercalation of a pseudomorphic monolayer of Cu in between graphene and Ir(111), using scanning tunnelling microscopy and photoelectron spectroscopy in combination with density functional theory calculations. We observe the modifications in the band structure by the intercalation process and its concomitant changes in the charge distribution at the interface. Through a state-selective analysis of band hybridization, we are able to determine their contributions to the valence band of graphene giving rise to the gap opening. Our methodology reveals the mechanisms that are responsible for the modification of the electronic structure of graphene at the Dirac point, and permits to predict the electronic structure of other graphene-metal interfaces.
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Vita
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Böttcher
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Horn
authors.affiliation: Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
authors.forename: E N
authors.initials: EN
authors.lastname: Voloshina
authors.affiliation: Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
authors.forename: R E
authors.initials: RE
authors.lastname: Ovcharenko
authors.affiliation: SPECS Surface Nano Analysis GmbH, Voltastraβe 5, 13355 Berlin, Germany.
authors.forename: Th
authors.initials: T
authors.lastname: Kampen
authors.affiliation: SPECS Surface Nano Analysis GmbH, Voltastraβe 5, 13355 Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Thissen
authors.affiliation: SPECS Surface Nano Analysis GmbH, Voltastraβe 5, 13355 Berlin, Germany.
authors.forename: Yu S
authors.initials: YS
authors.lastname: Dedkov