Excitation of electron-hole pairs in the vicinity of the Dirac cone by the
Coulomb interaction gives rise to an asymmetric Breit-Wigner-Fano lineshape in
the phonon Raman spectra in graphene. This asymmetric lineshape appears due to
the interference effect between the phonon spectra and the electron-hole pair
excitation spectra. The calculated Breit-Wigner-Fano asymmetric factor 1/qBWF
as a function of the Fermi energy shows a V-shaped curve with a minimum value
at the charge neutrality point and gives good agreement with the experimental
result.Comment: 15 pages, 4 figure
