Magnetic-field induced Electron-K-Phonon Interaction in the optical response of multi-layer epitaxial graphene

ORAL

Abstract

Absolute magneto-optical transmission measurements have been performed in the far-infra-red range under magnetic fields up to 32 T and at a temperature of 1.8 K on a series of multi-layer epitaxial graphene samples. In all samples, transmission data show for the main optical transition involving the n=0 landau level a clear splitting of the transition in the field range 17-18 T corresponding to an energy of about 150 meV which coincides with that of the K zone boundary phonon of graphene. A global analysis of the data using a multi-dielectric model, to fit them with a single transition, reveals in that range of energies an additional increase of the line-width accompanied by a softening of the transition energy. The energy variation of these quantities is characteristic of the emission of phonons. Possible origins of this effect will be discussed but seems to be the consequence of electron-electron interactions between the two valleys K and K' assisted by K-phonons between these two valleys.

–

Authors

  • Gerard Martinez

    LNCMI, CNRS, Grenoble, France, Laboratoire National des Champs Magetiques Intenses, CNRS

  • Milan Orlita

    Laboratoire National des Champs Magetiques Intenses, CNRS

  • Marek Potemski

    Laboratoire National des Champs Magetiques Intenses, CNRS

  • Mike Sprinkle

    School of Physics,Georgia Institute of Technology, Atlanta

  • Claire Berger

    School of Physics,Georgia Institute of Technology, Atlanta

  • Walt de Heer

    School of Physics,Georgia Institute of Technology, Atlanta, Georgia Institute of Technology

  • Liang Tan

    Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley

  • Steven G. Louie

    University of California, Berkeley and Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley National Lab, UC Berkeley, Department of Physics, U. C. Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, University of California-Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley, Phys Dept. UC Berkeley, Department of Physics, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, University of California at Berkeley and Lawrence Berkeley National Lab