title: Wave-function mapping of graphene quantum dots with soft confinement.
abstract: Using low-temperature scanning tunneling spectroscopy, we map the local density of states of graphene quantum dots supported on Ir(111). Because of a band gap in the projected Ir band structure around the graphene K point, the electronic properties of the QDs are dominantly graphenelike. Indeed, we compare the results favorably with tight binding calculations on the honeycomb lattice based on parameters derived from density functional theory. We find that the interaction with the substrate near the edge of the island gradually opens a gap in the Dirac cone, which implies soft-wall confinement. Interestingly, this confinement results in highly symmetric wave functions. Further influences of the substrate are given by the known moiré potential and a 10% penetration of an Ir surface resonance into the graphene layer.
authors.affiliation: II Physikalisches Institut B and JARA-FIT, RWTH Aachen University, D-52074 Aachen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Subramaniam
authors.forename: F
authors.initials: F
authors.lastname: Libisch
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Pauly
authors.forename: V
authors.initials: V
authors.lastname: Geringer
authors.forename: R
authors.initials: R
authors.lastname: Reiter
authors.forename: T
authors.initials: T
authors.lastname: Mashoff
authors.forename: M
authors.initials: M
authors.lastname: Liebmann
authors.forename: J
authors.initials: J
authors.lastname: Burgdörfer
authors.forename: C
authors.initials: C
authors.lastname: Busse
authors.forename: T
authors.initials: T
authors.lastname: Michely
authors.forename: R
authors.initials: R
authors.lastname: Mazzarello
authors.forename: M
authors.initials: M
authors.lastname: Pratzer
authors.forename: M
authors.initials: M
authors.lastname: Morgenstern