Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 109: Focus Session: Proximity Effects in Epitaxial Graphene II
O 109.2: Vortrag
Freitag, 22. März 2024, 11:00–11:15, MA 141
Charge density wave in highly-doped single-layer graphene — Vivien Enenkel1, Philipp Rosenzweig2, Hrag Karakachian2, Fabian Paschke1, Ulrich Starke2, and •Mikhail Fonin1 — 1Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany — 2Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
Recently, an emergence of electron correlation effects, such as superconductivity or charge density waves (CDW), in highly doped graphene monolayer has been predicted [1]. In our work, we perform Yb intercalation underneath zero-layer graphene on SiC to induce heavy electron doping in graphene. As reported previously, under Yd intercalation a van Hove singularity in graphene is pushed to the Fermi level, giving rise to an extended VHS, effectively pinning an almost non-dispersive flat band at EF [2]. We use low-temperature scanning tunneling microscopy to discriminate between different structures of Yb-intercalated graphene, which correspond to different Yb arrangements at the interface. For three structures, dI/dU measurements show a pronounced gap feature centered at EF. Together with strong changes of STM contrast upon bias voltage variation, the presence of the gap at EF points at the formation of a CDW state in the intercalated graphene monolayer. [1] M. L. Kiesel et al., Phys. Rev. B 86, 020507 (2012); [2] P. Rosenzweig et al., Phys. Rev. B 100, 035445 (2019).
Keywords: graphene; intercalation; doping; charge density wave