Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 98: Graphene VI
O 98.6: Vortrag
Freitag, 18. März 2011, 12:30–12:45, WIL A317
Scanning tunneling spectroscopy of confined states within graphene nanoislands — •Christian Pauly1, Dinesh Subramaniam1, Viktor Geringer1, Rafael Reiter2, Marco Pratzer1, Marcus Liebmann1, Carsten Busse3, Florian Libisch2, Thomas Michely3, and Markus Morgenstern1 — 1II. Physikalisches Institut B, RWTH Aachen University and JARA-FIT, Germany — 2Institut für theoretische Physik, Technische Universität Wien, Austria — 3II. Physikalisches Institut, Universität zu Köln, Germany
Epitaxial graphene islands are prepared by ethylene deposition on Ir(111) at room temperature and subsequent annealing to 1050°C. The lateral dimension of the islands varies from 5 nm to 40 nm. Using scanning tunneling spectroscopy we were able to visualize confined states within the islands. The state energies and corresponding local density of states patterns are in good agreement with third nearest neighbor tight-binding calculations for graphene. However, we had to include the potential of the moiré structure as well as a strongly absorbing character of the edge states. The width of the confined state energy peaks has been used to determine the lifetime of the Dirac electrons, which is inversely proportional to energy.