Electronic excitations and electron-phonon coupling in bulk graphite through Raman scattering in high magnetic fields

TL;DR

This study uses polarized magneto-Raman scattering at high magnetic fields to investigate electronic excitations and electron-phonon interactions in bulk graphite, revealing detailed Landau level dynamics and electron-hole asymmetry.

Contribution

It provides new insights into electron-phonon coupling and Landau band excitations in graphite using polarization-resolved magneto-Raman spectroscopy and the SWM model.

Findings

Observation of $K$-point electronic excitations with specific Landau band transitions.

Detection of the magneto-phonon effect involving the $E_{2g}$ phonon and Landau bands.

Quantification of electron-hole asymmetry in graphite.

Abstract

We use polarized magneto-Raman scattering to study purely electronic excitations and the electron-phonon coupling in bulk graphite. At a temperature of 4.2 K and in magnetic fields up to 28 T we observe $K$-point electronic excitations involving Landau bands with $\Delta |n|=0$ and with $\Delta |n|=\pm2$ that can be selected by controlling the angular momentum of the excitation laser and of the scattered light. The magneto-phonon effect involving the $E_{2g}$ optical phonon and $K$-point inter Landau bands electronic excitations with $\Delta |n|=\pm1$ is revealed and analyzed within a model taking into account the full $k_z$ dispersion. These polarization resolved results are explained in the frame of the Slonczewski-Weiss-McClure (SWM) model which directly allows to quantify the electron-hole asymmetry.