Regensburg 2013 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 77: Electronic Structure and Spin-Orbit Interaction III
O 77.6: Vortrag
Donnerstag, 14. März 2013, 17:15–17:30, H33
Mapping Image Potential States on Graphene Nanoflakes — Fabian Craes1, Sven Runte1, Jürgen Klinkhammer1, Marko Kralj2, Thomas Michely1, and •Carsten Busse1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Institut za fiziku, Zagreb, Croatia
Confinement effects of free electron like image potential states (IPSs) are observed in scanning tunneling spectroscopy (STS) on graphene nanoflakes on Ir(111) acting as potential wells. IPSs are unoccupied surface states energetically residing in an image charge potential between the Fermi and the vacuum level. They show a hydrogen-like spectrum perpendicular to the surface and form a two dimensional electron gas (2DEG) parallel to it.
We analyzed the IPSs by measuring local density of states (LDOS) point spectra as well as maps of the LDOS at selected energies. The spectra strongly depend on the size of the nanostructure as well as on the spatial position on top, indicating lateral confinement. The dominant contribution comes from a state other than the ground state due to parallel momentum transfer in the tunneling process. The confining potential can be tuned by intercalation.