Non-equilibrium Green's function theory for non-adiabatic effects in quantum transport: inclusion of electron-electron interactions

TL;DR

This paper extends non-equilibrium Green's function theory to include electron-electron interactions in quantum transport, accounting for non-adiabatic effects and dynamic molecular geometries, with applications to molecular junctions.

Contribution

It introduces a non-adiabatic Green's function approach for interacting electrons, incorporating nuclear velocities and accelerations into transport calculations.

Findings

Derived non-adiabatic Green's functions with electron-electron interactions.

Modified current formulas depend on nuclear velocities and accelerations.

Applied theory to a model molecular junction with local electron-electron repulsion.

Abstract

Non-equilibrium Green's function theory for non-adiabatic effects in quantum transport [Kershaw and Kosov, J.Chem. Phys. 2017, 147, 224109 and J. Chem. Phys. 2018, 149, 044121] is extended to the case of interacting electrons. We consider a general problem of quantum transport of interacting electrons through a central region with dynamically changing geometry. The approach is based on the separation of time scales in the non-equilibrium Green's functions and the use of Wigner transformation to solve the Kadanoff-Baym equations. The Green's functions and correlation self-energy are non-adiabatically expanded up to the second order central time derivatives. We produced expressions for Green's functions with non-adiabatic corrections and modified formula for electric current; both depend not only on instantaneous molecular junction geometry but also on nuclear velocities and accelerations. The theory is illustrated by the study of electron transport through a model single-resonant level molecular junction with local electron-electron repulsion and a dynamically changing geometry.