Ballistic transmission through a graphene bilayer

Abstract

We calculate the Fermi energy dependence of the (time-averaged) current and shot noise in an impurity-free carbon bilayer (length L width W), and compare with known results for a monolayer. At the Dirac point of charge neutrality, the bilayer transmits as two independent monolayers in parallel: Both current and noise are resonant at twice the monolayer value, so that their ratio (the Fano factor) has the same 1/3 value as in a monolayer-and the same value as in a diffusive metal. The range of Fermi energies around the Dirac point within which this pseudodiffusive result holds is smaller, however, in a bilayer than in a monolayer (by a factor l/L, with l the interlayer coupling length). © 2007 The American Physical Society.