Electron-phonon coupling and Raman spectroscopy in graphene

By A. C. Castro Neto, Francisco Guinea. 2006

150 citations recorded by the source corpus.

We show that the electron-phonon coupling in graphene, in contrast with the nonrelativistic two-dimensional electron gas, leads to shifts in the phonon frequencies that are nontrivial functions of the electronic density. These shifts can be measured directly in Raman spectroscopy. We show that depending whether the chemical potential is smaller (larger) than half of the phonon frequency, the frequency shift can negative (positive) relative to the neutral case (when the chemical potential is at the Dirac point), respectively. We show that the use of the static response function to calculate these shifts is incorrect and leads always to phonon softening. In samples with many layers, we find a shift proportional to the carrier concentration, and a splitting of the phonon frequencies if the charge is not homogeneously distributed. We also discuss the effects of edges in the problem.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/d95a2082b088038beb7ae0e5fa94fc046cb99007

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In Atomic and Molecular Physics, and Optics

In Electrical and Electronic Engineering

In Materials Chemistry

Citations in the corpus

Electronic properties of graphene in a strong magnetic field (2010, background): “Furthermore, the review by Castro Neto (Castro Neto et al., 2009) was concerned with general theoretical issues of electrons in graphene.”
Raman Spectroscopic Characterization of Graphene (2010, background): “The frequency of the G band of the suspended portion is similar to the single crystal of graphite ( 68 ) and the FWHM is similar to the highest value of charge neutrality graphene ( 69 – 75 ).”
The electronic properties of graphene (2007, background): “As dis ussed in (Castro et al., 2007b), thereis a band of surfa e states ompletely lo alized in the bottomlayer, and another surfa e band whi h alternates between thetwo.”