We analyze the response of bilayer graphene to an external transverse electric field using a variational method. A previous attempt to do so in a recent paper by Falkovsky [Phys. Rev. B 80, 113413 (2009)] is shown to be flawed. Our calculation reaffirms the original results obtained by one of us [E. McCann, Phys. Rev. B 74, 161403(R) (2006)] by a different method. Finally, we generalize these original results to describe a dual-gated bilayer graphene device.
@article{arxiv.1003.5607,
title = {Screening in gated bilayer graphene via variational calculus},
author = {M. M. Fogler and E. McCann},
journal= {arXiv preprint arXiv:1003.5607},
year = {2011}
}