Superconductivity of K-Intercalated Epitaxial Bilayer Graphene

Huempfner T, Otto F, Forker R, Müller P, Fritz T (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Advanced Materials Interfaces WILEY-VCH Verlag GmbH & Co. KGaA

DOI: 10.1002/admi.202300014

Abstract

Graphene-based materials are among the most promising candidates for studying superconductivity arising from reduced dimensionality. Apart from doping by twisted stacking, superconductivity can also be achieved by metal-intercalation of stacked graphene sheets, where the properties depend on the choice of the metal atoms and the number of graphene layers. Many different and even unconventional pairing mechanisms and symmetries are predicted in the literature for graphene monolayers and few-layers. However, those theoretical predictions have yet to be verified experimentally. Here, it is shown that potassium-intercalated epitaxial bilayer graphene is a superconductor with a critical temperature of Tc = 3.6 ± 0.1 K. By scanning-tunneling microscopy and angle-resolved photoelectron spectroscopy, the physical mechanisms are analyzed in great detail, using laboratory equipment. The data demonstrate that electron–phonon coupling is the driving force enabling superconductivity. Although the consideration of an s-wave pairing symmetry is sufficient to explain the experimental data, evidence is found for the existence of multiple energy gaps. Furthermore, it is shown that low-dimensional effects are most likely the cause of a gap ratio of 6.1 ± 0.2 that strongly exceeds the Bardeen-Cooper-Schrieffer (BCS) value of 3.52 for conventional superconductors. These results highlight the importance of reduced dimensionality yielding unusual superconducting properties of K-intercalated epitaxial bilayer graphene.

Authors with CRIS profile

Paul Müller Naturwissenschaftliche Fakultät

Involved external institutions

Friedrich-Schiller-Universität Jena DE Germany (DE)

How to cite

APA:

Huempfner, T., Otto, F., Forker, R., Müller, P., & Fritz, T. (2023). Superconductivity of K-Intercalated Epitaxial Bilayer Graphene. Advanced Materials Interfaces. https://dx.doi.org/10.1002/admi.202300014

MLA:

Huempfner, Tobias, et al. "Superconductivity of K-Intercalated Epitaxial Bilayer Graphene." Advanced Materials Interfaces (2023).

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