Anisotropic Eliashberg function and electron-phonon coupling in doped graphene

Autor(en)

D. Haberer, L. Petaccia, A. V. Fedorov, C. S. Praveen, S. Fabris, S. Piccinin, O. Vilkov, D. V. Vyalikh, A. Preobrajenski, N. I. Verbitskiy, H. Shiozawa, J. Fink, M. Knupfer, B. Buechner, Alexander Grüneis

Abstrakt

We investigate, with high-resolution angle-resolved photoemission

spectroscopy, the spectral function of potassium-doped

quasi-free-standing graphene on Au. Angle-dependent x-ray photoemission

and density functional theory calculations demonstrate that potassium

intercalates into the graphene/Au interface, leading to an upshift of

the K-derived electronic band above the Fermi level. This empty band is

what makes this system perfectly suited to disentangle the contributions

to electron-phonon coupling coming from the π band and K-derived bands. From a self-energy analysis we find an anisotropic electron-phonon coupling strength λ of 0.1 (0.2) for the KΓ (KM)

high-symmetry directions in momentum space, respectively.

Interestingly, the high-energy part of the Eliashberg function which

relates to graphene's optical phonons is equal in both directions but

only in KM does an additional low-energy part appear.

Organisation(en)

Elektronische Materialeigenschaften

Externe Organisation(en)

Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, University of California, Berkeley, Elettra Sincrotrone Trieste, Saint Petersburg State University, Theory@Elettra, Scuola Internazionale Superiore di Studi Avanzati, Technische Universität Dresden, Lund University

Journal

Physical Review B

Band

88

Anzahl der Seiten

5

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.88.081401

Publikationsdatum

08-2013

Peer-reviewed

Ja

ÖFOS 2012

103020 Oberflächenphysik, 103009 Festkörperphysik, 103018 Materialphysik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/d974a19f-c088-445a-b474-24e02cab88db