Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 33: Poster Graphene: Electronic Structure and Excitations
O 33.4: Poster
Dienstag, 18. März 2025, 13:30–15:30, P3
Quasi-freestanding monolayer graphene achieved by Pb intercalation — •S Wolff1, P Schädlich1, A D Peña Unigarro1, B Matta2, G Ghosal1, F Schölzel1, P Richter1, M Hutter3, M Stettner3, K Küster2, C Kumpf3, S Gemming1, U Starke2, C Tegenkamp1, and T Seyller1 — 1Institute of Physics, TU Chemnitz — 2MPI für Festkörperforschung, Stuttgart — 3Peter Grünberg Institut, Forschungszentrum Jülich
Intercalation is a promising approach for tailoring the electronic structure of epitaxial graphene on SiC. Beyond that, it enables the formation of otherwise unstable 2D phases of elements and opens a route to study the interplay between the two 2D materials and the substrate. We have studied the Pb intercalation process under the buffer layer in detail using low-energy electron microscopy (LEEM), photoelectron spectroscopy (PES), scanning tunneling microscopy (STM), density functional theory calculations (DFT) and X-ray standing wave (XSW). LEEM is used to monitor the intercalation process at different intercalation temperatures, resulting in either a (1×1) symmetry or in a (10×10) superstructure of the Pb atoms. These findings can be supported by angle-resolved PES and STM. Experiments indicate, in agreement with DFT, different filling of the Pb bands depending on the SiC polytype. Furthermore, XSW was used to determine the interlayer distances, revealing covalent bonding of the intercalant to the substrate and van der Waals bonding to graphene.
Keywords: graphene; intercalation