Phonon structures in the electronic density of states of graphene in magnetic field
Department of Physics, University of Guelph - Guelph, Ontario, Canada, N1G 2W1
2 Department of Physics and Astronomy, McMaster University - Hamilton, Ontario, Canada, L8S 4M1
3 The Canadian Institute for Advanced Research - Toronto, Ontario, Canada, M5G 1Z8
Accepted: 22 April 2011
Unlike in ordinary metals, in graphene, phonon structure can be seen in the quasiparticle electronic density of states, because the latter varies on the scale of the phonon energy. In a magnetic field, quantization into Landau levels creates even more significant variations. We calculate the density of states incorporating electron-phonon coupling in this case and find that the coupling has pronounced new effects: shifting and broadening of Landau levels, creation of new peaks, and splitting of any Landau levels falling near one of the new peaks. Comparing our calculations with a recent experiment, we find evidence for a phonon with energy similar to but somewhat greater than the optical E2g mode and a coupling corresponding to a mass enhancement parameter λ≃0.07.
PACS: 73.22.Pr – Electronic structure of graphene / 71.70.Di – Landau levels / 63.22.Rc – Phonons in graphene
© EPLA, 2011