Self-consistent analysis of electron-phonon coupling parameters of graphene

We present a self-consistent analysis of the photoemission spectral function A(k, w) of graphene monolayers grown epitaxially on SiC(0001). New information derived from spectral intensity anomalies (in addition to linewidths and peak positions) confirms that sizeable kinks in the electronic dispersion at the Dirac energy ED and near the Fermi level EF arise from many-body interactions, not single-particle effects such as substrate bonding or extra bands. The relative electron-phonon scattering rate from phonons at different energy scales evolves with doping. The electron-phonon coupling strength is extracted and found to be much larger (~3.5-5 times) than predicted.