Coulomb Drag and High Resistivity Behavior in Double Layer Graphene

We show that Coulomb drag in ultra-clean graphene double layers can be used for controlling the on/off ratio for current flow by tunning the external gate voltage. Hence, although graphene remains semi-metallic, the double layer graphene system can be tuned from conductive to a highly resistive state. We show that our results explain previous data of Coulomb drag in double layer graphene samples in disordered SiO2 substrates.