Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 77: Graphene V
O 77.4: Vortrag
Donnerstag, 17. März 2011, 15:45–16:00, WIL B321
Effect of the graphene moiré on Ir(111) on intercalated Eu patterns — •Daniel F. Förster1, Stefan Schumacher1, Tim Wehling3, Marin Petrović4, Iva Šrut4, Marko Kralj4, Petar Pervan4, Carsten Busse1, Achim Rosch2, and Thomas Michely1 — 1II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln — 2Institut für Theoretische Physik, Universität zu Köln, Zülpicher Str. 77, 50937 Köln — 3I. Institut für Theoretische Phsik, Universität Hamburg, Jungiusstr. 9, 20355 Hamburg — 4Institut za fiziku, Bijenicka 46, HR-10000 Zagreb
The electronic properties of graphene on a given substrate may be tailored by adsorption or intercalation.
We have grown Eu on graphene on Ir(111) between 45 K and 720 K with deposited amounts Θ in the monolayer regime. STM and LEED measurements, supported by DFT calculations, were used to determine the structure. Upon adsorption at 720 K Eu intercalates through point defects in the graphene. It forms intercalated line (small Θ) and line+island (larger Θ) patterns. Surprisingly, the line and island widths and spacings are integer units of the moiré cell dimensions. Depending on Θ the intercalated layer forms a p(2×2) or a (√3×√3)R30∘ superstructure with respect to the graphene lattice. As these structures are commensurate the moiré of graphene on Ir(111) is preserved. The intercalation patterns may be understood as a combined effect of the inhomogenous binding of graphene to Ir(111) within the moiré unit cell and of the elastic energy changes in graphene associated with intercalation.