Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 117: Graphene: Intercalation (jointly with O, HL)
TT 117.9: Talk
Friday, March 20, 2015, 12:30–12:45, MA 041
Enhancement of many-body effects observed on epitaxial monolayer graphene/Au/SiC(0001) — •Stiven Forti1, Stefan Link1, Alexander Stöhr1, Yuran Niu2, Alexei Zakharov2, and Ulrich Starke1 — 1Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart,Germany — 2Max-Lab, Lund University, Box 118, Lund, S-22100, Sweden
The interaction of graphene with gold atoms has gained high relevance for a series of reasons, from electrical contacts to plasmonics. Here we present the realization of n-type epitaxial monolayer graphene on SiC(0001) via the intercalation of a layer of Au atoms at the heterointerface between the graphene and the SiC substrate. Such a phase exhibits enhanced many-body effects, as observed by ARPES. The plasmaron band is observed and its dispersion is well discernible from the hole-Dirac cone. The effective dielectric constant extracted from the ARPES data is about five times smaller than what is reported in the literature so far. The effectiveness of the intercalation is corroborated by µLEED measurements, which clearly indicate a suppression of the diffraction spots on the (6√3×6√3)R30∘ grid, except for spots arising from multiple diffraction. CLPES measurements indicate the presence of a single gold component, namely assigned to gold silicides. The quality of the epitaxial graphene grown on SiC(0001) in Ar atmosphere, together with the aforementioned preparation, makes possible to observe bands of unprecedent sharpness for this system. Dispersive states arising from the 5d orbitals of the interfacial gold are observed as well, as predicted by theory.