Electron-phonon coupling-induced kinks in the sigma band of graphene

Federico Mazzola; Justin W. Wells; Rositza Yakimova; Soren Ulstrup; Jill A. Miwa; Richard Balog; Marco Bianchi; Mats Leandersson; Johan Adell; Philip Hofmann; T. Balasubramanian

arXiv · 1305.6210

Electron-phonon coupling-induced kinks in the sigma band of graphene

Federico Mazzola·Justin W. Wells·Rositza Yakimova·Soren Ulstrup·Jill A. Miwa·Richard Balog·Marco Bianchi·Mats Leandersson·Johan Adell·Philip Hofmann·T. Balasubramanian

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Abstract

Angle-resolved photoemission spectroscopy reveals pronounced kinks in the dispersion of the sigma band of graphene. Such kinks are usually caused by the combination of a strong electron-boson interaction and the cut-off in the Fermi-Dirac distribution. They are therefore not expected for the $σ$ band of graphene that has a binding energy of more than 3.5 eV. We argue that the observed kinks are indeed caused by the electron-phonon interaction, but the role of the Fermi-Dirac distribution cutoff is assumed by a cut-off in the density of $σ$ states. The existence of the effect suggests a very weak coupling of holes in the $σ$ band not only to the $π$ electrons of graphene but also to the substrate electronic states. This is confirmed by the presence of such kinks for graphene on several different substrates that all show a strong coupling constant of lambda=1.

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Federico Mazzola, Justin W. Wells, Rositza Yakimova, Soren Ulstrup, Jill A. Miwa, Richard Balog, Marco Bianchi, Mats Leandersson, Johan Adell, Philip Hofmann, T. Balasubramanian. 2013-06-01. Electron-phonon coupling-induced kinks in the sigma band of graphene. https://arxiv.org/abs/1305.6210

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