Effect of Holstein phonons on the optical conductivity of gapped graphene

TL;DR

This paper investigates how Holstein phonons influence the optical conductivity of gapped, doped graphene with broken sublattice symmetry, revealing new features in self-energy and deriving an analytical expression for the renormalized Fermi velocity.

Contribution

It provides a novel analytical expression for the renormalized Fermi velocity of massive Dirac fermions considering electron-phonon interactions and band gap effects.

Findings

New features in real and imaginary parts of quasiparticle self-energy due to gap opening

Analytical expression for renormalized Fermi velocity across various parameters

Importance of including Fermi energy and band gap effects in optical conductivity analysis

Abstract

We study the optical conductivity of a doped graphene when a sublattice symmetry breaking is occurred in the presence of the electron-phonon interaction. Our study is based on the Kubo formula that is established upon the retarded self-energy. We report new features of both the real and imaginary parts of the quasiparticle self-energy in the presence of a gap opening. We find an analytical expression for the renormalized Fermi velocity of massive Dirac Fermions over broad ranges of electron densities, gap values and the electron-phonon coupling constants. Finally we conclude that the inclusion of the renormalized Fermi energy and the band gap effects are indeed crucial to get reasonable feature for the optical conductivity.