Authors

A. Ferreira; J. Viana-Gomes; J. Nilsson; E. R. Mucciolo; N. M. R. Peres;A. H. Castro Neto

Comments

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Abbreviated Journal Title

Phys. Rev. B

Keywords

TRANSPORT; FILMS; Physics, Condensed Matter

Abstract

We show that a coherent picture of the dc conductivity of monolayer and bilayer graphene at finite electronic densities emerges upon considering that strong short-range potentials are the main source of scattering in these two systems. The origin of the strong short-range potentials may lie in adsorbed hydrocarbons at the surface of graphene. The equivalence among results based on the partial-wave description of scattering, the Lippmann-Schwinger equation, and the T-matrix approach is established. Scattering due to resonant impurities close to the neutrality point is investigated via a numerical computation of the Kubo formula using a kernel polynomial method. We find that relevant adsorbate species originate impurity bands in monolayer and bilayer graphene close to the Dirac point. In the midgap region, a plateau of minimum conductivity of about e(2)/h ( per layer) is induced by the resonant disorder. In bilayer graphene, a large adsorbate concentration can develop an energy gap between midgap and high-energy states. As a consequence, the conductivity plateau is supressed near the edges and a "conductivity gap" takes place. Finally, a scattering formalism for electrons in biased bilayer graphene, taking into account the degeneracy of the spectrum, is developed and the dc conductivity of that system is studied.

Journal Title

Physical Review B

Volume

83

Issue/Number

16

Publication Date

1-1-2011

Document Type

Article

Language

English

First Page

22

WOS Identifier

WOS:000289054400005

ISSN

1098-0121

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