Electric Field Effect Tuning of Electron-Phonon Coupling in Graphene

TL;DR

This study demonstrates how electric field effects modulate electron-phonon interactions in graphene, revealing changes in phonon properties linked to Dirac fermions and charge carrier density.

Contribution

It provides experimental evidence of electric field tuning of electron-phonon coupling in graphene via Raman spectroscopy, highlighting the role of Dirac fermions.

Findings

Phonon frequency shifts linearly with Fermi energy.

Particle-hole symmetry observed around the Dirac point.

Electric field influences electron-phonon interactions in graphene.

Abstract

Gate-modulated low-temperature Raman spectra reveal that the electric field effect (EFE), pervasive in contemporary electronics, has marked impacts on long wavelength optical phonons of graphene. The EFE in this two dimensional honeycomb lattice of carbon atoms creates large density modulations of carriers with linear dispersion (known as Dirac fermions). Our EFE Raman spectra display the interactions of lattice vibrations with these unusual carriers. The changes of phonon frequency and line-width demonstrate optically the particle-hole symmetry about the charge-neutral Dirac-point. The linear dependence of the phonon frequency on the EFE-modulated Fermi energy is explained as the electron-phonon coupling of mass-less Dirac fermions.