We present a systematic Raman study of unconventionally-stacked double-layer graphene, and find that the spectrum strongly depends on the relative rotation angle between layers. Rotation-dependent trends in the position, width and intensity of graphene 2D and G peaks are experimentally established and accounted for theoretically. Our theoretical analysis reveals that changes in electronic band structure due to the interlayer interaction, such as rotational-angle dependent Van Hove singularities, are responsible for the observed spectra features. Our combined experimental and theoretical study provides a deeper understanding of the electronic band structure of rotated double-layer graphene, and leads to a practical way to identify and analyze rotation angles of misoriented double-layer graphene.
@article{arxiv.1201.4221,
title = {Raman spectroscopy study of rotated double-layer graphene: Misorientation-angle dependence of electronic structure},
author = {Kwanpyo Kim and Sinisa Coh and Liang Z. Tan and William Regan and Jong Min Yuk and Eric Chatterjee and M. F. Crommie and Marvin L. Cohen and Steven G. Louie and A. Zettl},
journal= {arXiv preprint arXiv:1201.4221},
year = {2012}
}
Comments
To appear in Phys. Rev. Lett., added extra data, 22 pages with 10 figures (including 6 supplementary figures)