SKM 2023 – scientific programme
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O: Fachverband Oberflächenphysik
O 64: Poster: Graphene
O 64.6: Poster
Wednesday, March 29, 2023, 18:00–20:00, P2/EG
Electronic band structure of Pb intercalated graphene on SiC and the influence of electron doping — •Bharti Matta1, Philipp Rosenzweig1, Kathrin Küster1, Craig Polley2, and Ulrich Starke1 — 1Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany — 2MAX IV Laboratory, Lund University, Fotongatan 2, Lund 22484, Sweden
Intercalation is a powerful way of modifying the properties of epitaxial graphene and stabilizing two-dimensional (2D) intercalant layers at the graphene/SiC interface. In this work, we show that the charge neutrality of Pb intercalated quasi-freestanding monolayer graphene on SiC involves charge transfer from both the intercalant and the substrate. Synchrotron based angle resolved photoelectron spectroscopy measurements demonstrate the (1×1) order of the Pb layer with respect to SiC. The interlayer bands cross the Fermi level, confirming the metallic nature of intercalated Pb. Furthermore, constant initial state mapping shows no dispersion of the Pb bands with photon energy, proving the 2D nature of the intercalant layer. Polarization dependent measurements retrieve a mainly in-plane orbital character for the Pb band branches closer to the Fermi energy. Potassium deposition induces strong n-doping in the graphene layer (ED ≈ 1.1 eV). However, the Pb bands do not show any noticeable change, which suggests that the charge transfer from the potassium layer occurs predominantly into the graphene. Supported by DFG through FOR 5242.