Diffusive transport in graphene: The role of interband correlation

We present a kinetic equation approach to investigate dc transport properties of graphene in the diffusive regime considering long-range electron-impurity scattering. In our study, the effects of interband correlation (or polarization) on conductivity are taken into account. We find that the conductivity contains not only the usual term inversely proportional to impurity density N-i but also an anomalous term that is linear in Ni. This leads to a minimum in the density dependence of conductivity when the electron density N-e is equal to a finite critical value N-c. The effects of various scattering potentials on the conductivity minimum are also analyzed. Using typical experimental parameters, we find that for random-phase-approximation-screened electron-impurity scattering, the minimum conductivity is about 4.42e(2)/h when Ne approximate to 0.11 N-i, and the conductivity varies almost linearly with the electron density for N-e > N-i. (c) 2008 American Institute of Physics.