Low B Field Magneto-Phonon Resonances in Single-Layer and Bilayer Graphene

TL;DR

This paper investigates low magnetic field magneto-phonon resonances in high-quality single-layer and bilayer graphene, revealing effects of many-body interactions and enabling extraction of effective Fermi velocities and resonance broadening characteristics.

Contribution

It provides new experimental insights into many-body effects in graphene through magneto-phonon resonance measurements at low magnetic fields.

Findings

Effective Fermi velocities up to 1.20 x 10^6 m/s were measured.

Resonance broadening increases with Landau level index.

Manifestation of many-body effects in low B field magneto-phonon resonances.

Abstract

Many-body effects resulting from strong electron-electron and electron-phonon interactions play a significant role in graphene physics. We report on their manifestation in low B field magneto-phonon resonances in high quality exfoliated single-layer and bilayer graphene encapsulated in hexagonal boron nitride. These resonances allow us to extract characteristic effective Fermi velocities, as high as $1.20 \times 10^6$ m/s, for the observed "dressed" Landau level transitions, as well as the broadening of the resonances, which increases with Landau level index.