We describe a peculiar fine structure acquired by the in-plane optical phonon at the Gamma-point in graphene when it is brought into resonance with one of the inter-Landau-level transitions in this material. The effect is most pronounced when this lattice mode (associated with the G-band in graphene Raman spectrum) is in resonance with inter-Landau-level transitions 0 -> (+,1) and (-,1) -> 0, at a magnetic field B_0 ~ 30 T. It can be used to measure the strength of the electron-phonon coupling directly, and its filling-factor dependence can be used experimentally to detect circularly polarized lattice modes.
@article{arxiv.0704.0027,
title = {Filling-Factor-Dependent Magnetophonon Resonance in Graphene},
author = {M. O. Goerbig and J. -N. Fuchs and K. Kechedzhi and Vladimir I. Fal'ko},
journal= {arXiv preprint arXiv:0704.0027},
year = {2009}
}
Comments
4 pages, 2 figures; mistakes due to an erroneous electron-phonon coupling constant have been corrected; mode splitting is larger than originally expected