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O: Fachverband Oberflächenphysik
O 73: Graphene: Growth, structure and substrate interaction – Poster
O 73.5: Poster
Mittwoch, 11. März 2026, 18:00–20:00, P2
Ca-intercalation of epitaxial monolayer graphene — Luqman Mahdi Syed1,2, Niclas Tilgner1,2, •Philip Schädlich1,2, and Thomas Seyller1,2 — 1Institut für Physik, Technische Universität Chemnitz — 2Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Technische Universität Chemnitz
Realizing proximity-induced correlation effects, such as superconductivity, in graphene is a major challenge in the field of research on two-dimensional (2D) materials. Among the graphite intercalation compounds (GICs), the Ca-GICs exhibit the highest critical temperature with Tc=11.5 K, where the electron doping from the Ca atoms may be a crucial factor. Hence, expanding this superconducting phase into the 2D limit of epitaxial monolayer graphene (EMLG) on SiC(0001) requires precise control over the arrangement of the intercalated Ca atoms. However, several structural models have been proposed for Ca-intercalated EMLG, and in particular, the vertical position - i.e., the gallery - in which Ca resides remains unresolved (S. Ichinokura et al. 2016 ACS Nano 10 2761, J.C. Kotsakidis et al. 2020 Chem. Mater. 32 (15) 6464). Here, we investigate Ca-intercalation into EMLG grown by polymer-assisted sublimation growth. Using x-ray and angle-resolved photoemission spectroscopy, we monitor the intercalation process and quantify the doping level. Our results indicate the saturation of the SiC interface by Ca. We observe the low-energy bands of the resulting intercalated bilayer graphene, and more interstingly regarding the superconducting state, a highly doped graphene π-band, which may point towards the presence of calcium in the upper gallery.
Keywords: Epitaxial graphene; Intercalation; Superconductivity; Photoelectron Spectroscopy; Polymer-assisted sublimation growth