Raman scattering study of the phonon dispersion in twisted bilayer graphene
twisted bilayer graphene, Raman spectroscopy, phonon branches
Bilayer graphene with a twist angle θ between the layers generates a superlattice structure known as a Moiré pattern. This superlattice provides a θ-dependent q wavevector that activates phonons in the interior of the Brillouin zone. Here we show that this superlattice-induced Raman scattering can be used to probe the phonon dispersion in twisted bilayer graphene (tBLG). The effect reported here is different from the widely studied double-resonance in graphene-related materials in many aspects, and despite the absence of stacking order in tBLG, layer breathing vibrations (namely ZO’ phonons) are observed.
Tsinghua University Press
Jessica Campos-Delgado,Luiz G. Cançado,Carlos A. Achete,Ado Jorio,Jean-Pierre Raskin, Raman scattering study of the phonon dispersion in twisted bilayer graphene. NanoRes.2013, 6(4): 269–274