Landau level-phonon resonances in graphene and their spectroscopic signatures in magneto-optical measurements

The excited states and the optical spectra of a two-dimensional electronic system under a magnetic field are strongly influenced by the electron-phonon interaction when the energy spacing of the Landau levels is resonant with the frequency of an optical phonon. We have performed a theoretical study of these excited states in graphene, and have calculated the optical absorption spectra for a range of magnetic fields. Electron-electron interactions are found to redistribute the spectral weight of the coupled modes and have important consequences for the absorption spectra. Our results are in good agreement with recent magneto-optical transmission experiments on epitaxial graphene on SiC. This work was supported by NSF Grant No. DMR10-1006184 and U.S. DOE Contract No. DE- AC02-05CH11231.