Magneto-Coulomb Drag in Double Layer Graphene

We report on our theoretical investigations on the Coulomb drag in double-layer graphene in strong magnetic fields. Using diagrammatic perturbation theory, we obtain explicit analytical expressions for the nonlinear susceptibility and the drag conductivity. At low temperatures $T$, the drag conductivity behaves as $\mathrm{exp}(-\Delta/T)/T$, where $\Delta$ is the inter-Landau level transition energy nearest to the Fermi level. For full filling at the zeroth Landau level, we find a non-vanishing drag that arises from the intrinsic contribution of filled Landau levels below the Dirac point.