Coulomb drag between quantum wires: A nonequilibrium many-body approach

Abstract

We present a real-space theoretical formalism and its numerical implementation for investigating nonequilibrium quantum Coulomb drag between parallel two-terminal transport structures in quasi-one-dimension. In addition to the Coulomb interaction and the finite external potential bias, our formalism takes into account the effects of impurity disorder. The theory is formulated in the nonequilibrium Green's function formalism, with the long-range Coulomb interaction treated at the many-body GW approximation level and the disorder-average carried out at the coherent potential approximation (CPA) level. The coupled GW and CPA equations are solved self-consistently so that the fundamental conservation laws are ensured. The effects related to the electron-hole symmetry in the Coulomb drag physics have been generalized to the nonlinear transport regime. A set of symmetry-induced relations linking physical quantities with the particle distribution were established on generic footing and, remarkably, they are found robust against uniformly distributed impurities. As an application, the theoretical formalism is employed to analyze the Coulomb drag transport physics in quasi-one-dimensional systems. The dependencies of the drag current on external bias, chemical potential, temperature, and the system sizes are predicted.