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O: Fachverband Oberflächenphysik
O 4: Graphene I
O 4.5: Vortrag
Montag, 26. März 2012, 11:30–11:45, MA 041
Adsorption effects on the electronic and magnetic properties of nanosized Graphene structures on the Ir(111) Surface — •Yan Li1, Dinesh Subramaniam1, Nicolae Atodiresei2, Predrag Lazic3, Vasile Caciuc2, Marcus Liebmann1, Marco Pratzer1, Christian Pauly1, Alexander Georgi1, Riccardo Mazzarello1, Stefan Blugel2, and Markus Morgenstern1 — 1RWTH Aachen, Aachen, Germany — 2Forschungszentrum Jülich, Jülich, Germany — 3MIT, Massachusetts, USA
We have studied the structural, electronic and magnetic properties of graphene nanoribbons and flakes grown on the Ir(111) surface by ab initio simulations and low-temperature scanning tunneling spectroscopy. The calculated formation energy and the experimental STM images indicate that in zigzag terminated flakes each C atom at the edge is saturated by one hydrogen atom. Due to the interplay between a) the strong interaction between Ir atoms and C atoms at the edge and b) the lattice mismatch, a superstructure consisting of alternating regions of strongly bound, sp3-hybridized C atoms and weakly bound, sp2-hybridized C atoms is formed at the edge. As a result of the interaction with the surface, no magnetic edge state near the Fermi level exists in the supported ribbon: this conclusion is corroborated by both calculation and experiments. We also studied theoretically the electronic structure of unsaturated nanoribbons on the same surface. No magnetic edge state was obtained in this system either.