We present a first-principles study of the electron-phonon (e-ph) interactions and their contributions to the linewidths for the optical phonon modes at Γ and K in one to three-layer graphene. It is found that due to the interlayer coupling and the stacking geometry, the high-frequency optical phonon modes in few-layer graphene couple with different valence and conduction bands, giving rise to different e-ph interaction strengths for these modes. Some of the multilayer optical modes derived from the Γ-E2g mode of monolayer graphene exhibit slightly higher frequencies and much reduced linewidths. In addition, the linewidths of K-A1′ related modes in multilayers depend on the stacking pattern and decrease with increasing layer numbers.
@article{arxiv.0901.3086,
title = {Electron-Phonon Interactions for Optical Phonon Modes in Few-Layer Graphene},
author = {Jia-An Yan and W. Y. Ruan and M. Y. Chou},
journal= {arXiv preprint arXiv:0901.3086},
year = {2009}
}