Raman-scattering study of the phonon dispersion in twisted bi-layer graphene
arXiv:1301.3795 · doi:10.1007/s12274-013-0304-z
Abstract
Bi-layer graphene with a twist angle θ between the layers generates a superlattice structure known as 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 bi-layer graphene (tBLG). The effect reported here is different from the broadly 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.
18 pages, 4 figures, research article