Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 33: Poster Graphene: Electronic Structure and Excitations
O 33.1: Poster
Tuesday, March 18, 2025, 13:30–15:30, P3
Reversible transition between (10 × 10) and (11 × 11) phases of Pb intercalated EG on 6H/SiC(0001) — •Sergii Sologub1,2, Markus Gruschwitz2, Bharti Matta3, Andres David Pena Unigarro2, Philipp Rosenzweig3, Sibylle Gemming2, Kathrin Küster3, Ulrich Starke3, and Christoph Tegenkamp2 — 1Institute of Physics, NAS of Ukraine, Kyiv — 2Institut für Physik, TU Chemnitz, Chemnitz — 3Max-Planck-Institut für Festkörperforschung, Stuttgart
Epitaxial graphene (EG) obtained by intercalation of a buffer layer on 6H/SiC(0001) with Pb atoms is the subject of intensive experimental and theoretical studies due to its charge neutrality, the band gap opening and proximity superconductivity. The hallmark of Pb-intercalated EG is the formation of diffraction spots with (10 × 10) or (11 × 11) periodicity in the high-resolution LEED patterns. The correlation between these phases and corresponding microstructure, i.e. “striped” and “bubble” Pb intercalated phases, were examined by STM and by dark field imaging in a photoemission electron microscope. We have also established a recipe to reversibly switch between the (10 × 10) and (11 × 11) structures. In addition, the ratio of areas occupied by these coexisting phases could be estimated from the intensity ratio of second order LEED spots. Importantly, the degree and ease of intercalation strongly depends on the defect density of the initial buffer layer. The transformation between the different phases can be rationalized by the low diffusion barrier of Pb on SiC observed by density functional calculations.
Keywords: epitaxial graphene; intercalation; lead