It is always said that the Kohn anomaly of graphene is moved away from the gamma point, when graphene is doped.
I am confused about such discription. What will the phonon dispersion look like at that time (when doped)? Where is the Kohn anomaly moved to? Is the kink (Kohn anomaly) of the phonon dispersion curve smoothed or the kink moved to somewhere else?
ref:
'Doping changes the Fermi surface of graphene. This moves
the Kohn anomaly away from q = 0'
in 'Raman spectroscopy of graphene and graphite: Disorder, electron–phonon coupling, doping and nonadiabatic effects' by Prof. Andrea C.Ferrari
I t depends on how fast you do your doping. The phonon dispersion curve is usually smooth.
Dear Nehme,
Thank you for your answer!
I do not understand your meaning. Why do you consider about the speed of doping?
And, the Kohn anomaly appears as a kink in the phonon dispersion, i.e. an abrupt drop of energy at a specific wavevector. My question is about this sudden change of phonon dispersion at the Γ ponit, as is shown in the attached picture.
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