We perform Raman scattering experiments on natural graphite in magnetic fields up to 45 T, observing a series of peaks due to interband electronic excitations over a much broader magnetic field range than previously reported. We also explore electron-phonon coupling in graphite via magnetophonon resonances. The Raman $G$ peak shifts and splits as a function of magnetic field, due to the magnetically tuned coupling of the $E_{2g}$ optical phonons with the $K$- and $H$-point inter-Landau-level excitations. The analysis of the observed anticrossing behavior allows us to determine the electron-phonon coupling for both $K$- and $H$-point carriers. In the highest field range ($>$35 T) the $G$ peak narrows due to suppression of electron-phonon interaction.

• Received 14 December 2011

DOI:https://doi.org/10.1103/PhysRevB.85.121403