Random-gap model for graphene and graphene bilayers.
The effect of a randomly fluctuating gap, created by a random staggered potential, is studied in a monolayer and a bilayer of graphene. The density of states, the one-particle scattering rate, and the transport properties (diffusion coefficient and conductivity) are calculated at the neutrality point. All of these quantities vanish at a critical value of the average staggered potential, signaling a continuous transition to an insulating behavior. Transport quantities are directly linked to the one-particle scattering rate. Although the behavior is qualitatively the same in mono- and bilayers, the effect of disorder is much stronger in the latter.
Ziegler
K
K
Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany. Klaus.Ziegler@Physik.Uni-Augsburg.de