We study the optical conductivity in the low-energy regime of gapped mono- and bilayer graphene. A scaling relation is found, in which the four parameters frequency, gap, Fermi energy and temperature appear only as combination of three independent parameters. The ratio of the optical conductivity of bilayer and mononlayer graphene is exactly 2.
@article{arxiv.1001.3366,
title = {Robust optical conductivity in gapped graphene},
author = {K. Ziegler and A. Sinner},
journal= {arXiv preprint arXiv:1001.3366},
year = {2010}
}