title: One-parameter scaling at the dirac point in graphene.
abstract: We numerically calculate the conductivity sigma of an undoped graphene sheet (size L) in the limit of a vanishingly small lattice constant. We demonstrate one-parameter scaling for random impurity scattering and determine the scaling function beta(sigma)=dlnsigma/dlnL. Contrary to a recent prediction, the scaling flow has no fixed point (beta>0) for conductivities up to and beyond the symplectic metal-insulator transition. Instead, the data support an alternative scaling flow for which the conductivity at the Dirac point increases logarithmically with sample size in the absence of intervalley scattering--without reaching a scale-invariant limit.
authors.affiliation: Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: Bardarson
authors.forename: J
authors.initials: J
authors.lastname: Tworzydło
authors.forename: P W
authors.initials: PW
authors.lastname: Brouwer
authors.forename: C W J
authors.initials: CW
authors.lastname: Beenakker