Regensburg 2022 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 41: Graphene: Growth, Substrate Interaction, Intercalation, and Doping

O 41.6: Vortrag

Mittwoch, 7. September 2022, 11:45–12:00, S052

Structural and electronic properties of a van der Waals heterostructure of two-dimensional Pb and epitaxial graphene — •Bharti Matta, Philipp Rosenzweig, Olaf Bolkenbaas, Kathrin Küster, and Ulrich Starke — Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany

Intercalation is an established technique for manipulating the electronic properties of epitaxial graphene. Moreover, it is a way to confine otherwise unstable two-dimensional (2D) layers of elements, leading to unique physical properties compared to their bulk counterparts due to quantum confinement. In this work, we show uniformly Pb-intercalated quasi-freestanding monolayer graphene on SiC, which turns out to be essentially charge neutral. Additional bands – some crossing the Fermi level – can be clearly discerned, demonstrating the metallic character of 2D Pb sandwiched within the graphene/SiC heterointerface. The band velocity of the graphene Dirac cone changes at binding energies of around 0.6 eV and 1.1 eV, which points towards hybridization with these Pb bands. Low-energy electron diffraction reveals a 10×10 Moiré periodicity with respect to graphene. This is consistent with a triangular lattice of intercalated Pb that is strained by less than 2% relative to bulk-truncated Pb(111) and of which a (√3×√3)R30^∘ supercell matches 2×2-SiC. However, finding direct signatures of the corresponding periodicities in the available band structure data is challenging. Our experimental results will provide a solid ground for further theoretical assessment of this system and better understanding of its properties.