Quantum noise and asymmetric scattering of electrons and holes in graphene.

We present measurements of quantum interference noise in double-gated single layer graphene devices at low temperatures. The noise characteristics show a nonmonotonic dependence on carrier density, which is related to the interplay between charge inhomogeneity and different scattering mechanisms. Linearly increasing 1/f noise at low carrier densities coincides with the observation of weak localization, suggesting the importance of short-range disorder in this regime. Using perpendicular and parallel p-n junctions, we find that the observed asymmetry of the noise with respect to the Dirac point can be related to asymmetric scattering of electrons and holes on the disorder potential.