Observation of a universal donor-dependent vibrational mode in graphene

Author(s)
A. V. Fedorov, N. I. Verbitskiy, D. Haberer, C. Struzzi, L. Petaccia, D. Usachov, O. Y. Vilkov, D. V. Vyalikh, J. Fink, M. Knupfer, B. Buchner, A. Gruneis
Abstract

Electron–phonon coupling and the emergence of superconductivity in intercalated graphite have been studied extensively. Yet, phonon-mediated superconductivity has never been observed in the 2D equivalent of these materials, doped monolayer graphene. Here we perform angle-resolved photoemission spectroscopy to try to find an electron donor for graphene that is capable of inducing strong electron–phonon coupling and superconductivity. We examine the electron donor species Cs, Rb, K, Na, Li, Ca and for each we determine the full electronic band structure, the Eliashberg function and the superconducting critical temperature Tc from the spectral function. An unexpected low-energy peak appears for all dopants with an energy and intensity that depend on the dopant atom. We show that this peak is the result of a dopant-related vibration. The low energy and high intensity of this peak are crucially important for achieving superconductivity, with Ca being the most promising candidate for realizing superconductivity in graphene.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Saint Petersburg State University, Anuchin Research Institute and Museum of Anthropology, University of California, Berkeley, Elettra-Sincrotrone Trieste S.C.p.A., Technische Universität Dresden
Journal
Nature Communications
Volume
5
No. of pages
8
ISSN
2041-1723
DOI
https://doi.org/10.1038/ncomms4257
Publication date
02-2014
Peer reviewed
Yes
Austrian Fields of Science 2012
103020 Surface physics, 103018 Materials physics, 103009 Solid state physics
Keywords
ASJC Scopus subject areas
Physics and Astronomy(all), Chemistry(all), Biochemistry, Genetics and Molecular Biology(all)
Portal url
https://ucris.univie.ac.at/portal/en/publications/observation-of-a-universal-donordependent-vibrational-mode-in-graphene(09b16941-3444-4d18-89fb-6988a57fa4ba).html