Comment on “Raman spectra of misoriented bilayer graphene”

Abstract

In a recent paper, Poncharal et al. [Phys. Rev. B 78, 113407 (2008)] studied the Raman spectra of misoriented bilayer graphene. They found that the blueshift of 2D band of misoriented graphene relative to that of single layer graphene shows a strong dependence on the excitation laser energy. The blueshift increases with decreasing excitation energy. This finding contradicts our explanation of reduction in Fermi velocity of folded/misoriented graphene [Ni et al., Phys. Rev. B 77, 235403 (2008)]. In this Comment, we present more experimental results from our group as well as from others to show that the blueshift is indeed only weakly dependent on excitation energy. We therefore suggest that our explanation of 2D blueshift of folded graphene due to reduction in Fermi velocity is still valid.