Coulomb drag by motion of a monolayer polar crystal through graphene nanoconstriction

Abstract: We theoretically predict that the motion of a polar crystalline layer between two graphene planes exerts Coulomb drag on electrons in graphene, inducing a DC drag current. The physical mechanism underlying this drag arises from intervalley scattering of charge carriers in graphene caused by the time-dependent potential of the moving crystalline layer. This drag effect manifests above a finite threshold doping of the graphene layers, which is determined by the lattice structure and the relative orientation of the crystalline layer with respect to the graphene lattice. Additionally, the drag current exhibits a nonlinear Hall effect due to the interplay between the induced nonequilibrium pseudospin and the intrinsic pseudospin-orbit coupling in graphene. In turn, the drag exerted on electrons in graphene produces a backaction on the crystalline layer, which can be described as an increase in its dynamic viscosity.