Effects of Electron-Electron Interactions on Electronic Raman Scattering of Graphite in High Magnetic Fields

TL;DR

This study investigates how electron-electron interactions influence the electronic Raman scattering spectra of graphite under high magnetic fields, revealing temperature-dependent spectral line asymmetries explained by Tomonaga-Luttinger liquid theory.

Contribution

The paper demonstrates the application of Tomonaga-Luttinger liquid theory to interpret temperature-dependent spectral features in high-field graphite Raman scattering.

Findings

Spectral lines are strongly temperature-dependent and asymmetric.

Interaction effects modify the van Hove singularity to a specific power-law form.

The model accurately reproduces the observed line-shape and determines the interaction parameter α.

Abstract

We report the observation of strongly temperature-dependent, asymmetric spectral lines in electronic Raman scattering spectra of graphite in a high magnetic field up to 45 T applied along the c-axis. The magnetic field quantizes the in-plane motion, while the out-of-plane motion remains free, effectively reducing the system dimension from three to one. Optically created electron-hole pairs interact with, or shake up, the one-dimensional Fermi sea in the lowest Landau subbands. Based on the Tomonaga-Luttinger liquid theory, we show that interaction effects modify the van Hove singularity to the form $(\omega-\Delta)^{2\alpha-1/2}$ at zero temperature. At finite temperature, we predict a thermal broadening factor that increases linearly with the temperature. Our model reproduces the observed temperature-dependent line-shape, determining $\alpha$ to be $\sim$0.05 at 40 T.