Theory of resonant multiphonon Raman scattering in graphene

TL;DR

This paper develops a theoretical framework for calculating the intensities of multiphonon Raman peaks in graphene, linking symmetry-based Hamiltonian parameters to experimental data.

Contribution

It introduces a symmetry-based low-energy Hamiltonian with a minimal set of parameters to describe multiphonon Raman scattering in graphene.

Findings

Calculated Raman peak intensities match experimental data

Extracted coupling constants from measurements

Provided a unified symmetry-based theoretical approach

Abstract

We present a detailed calculation of intensities of two-phonon and four-phonon Raman peaks in graphene. Writing the low-energy hamiltonian of the interaction of electrons with the crystal vibrations and the electromagnetic field from pure symmetry considerations, we describe the system in terms of just a few independent coupling constants, considered to be parameters of the theory. The electron scattering rate is introduced phenomenologically as another parameter. The results of the calculation are used to extract information about these parameters from the experimentally measured Raman peak intensities.