First-principles studies of the electron-phonon coupling in graphene predict a high coupling strength for the σ band with λ values of up to 0.9. Near the top of the σ band, λ is found to be ≈0.7. This value is consistent with the recently observed kinks in the σ band dispersion by angle-resolved photoemission. While the photoemission intensity from the σ band is strongly influenced by matrix elements due to sub-lattice interference, these effects differ significantly for data taken in the first and neighboring Brillouin zones. This can be exploited to disentangle the influence of matrix elements and electron-phonon coupling. A rigorous analysis of the experimentally determined complex self-energy using Kramers-Kronig transformations further supports the assignment of the observed kinks to strong electron-phonon coupling and yields a coupling constant of 0.6(1), in excellent agreement with the calculations.
@article{arxiv.1607.00939,
title = {Strong electron-phonon coupling in the sigma band of graphene},
author = {Federico Mazzola and Thomas Frederiksen and Thiagarajan Balasubramanian and Philip Hofmann and Bo Hellsing and Justin W. Wells},
journal= {arXiv preprint arXiv:1607.00939},
year = {2017}
}