Non-equilibrium charge transport through molecular junctions as stochastic many-electron dynamics

Abstract

To study time-resolved electric currents through molecular electronic systems, it is common to use real-time time-dependent functional theory, non-equilibrium Green’s function, or the driven Liouville–von Neumann method, among others. These approaches are based either on the one-electron density or on the one-electron density matrix theory, and attempts to treat electron transport from a many-electron perspective are few and far apart. In this contribution, we take the first step toward describing charge transport through a molecular nanojunction as a stochastic many-electron dynamics treated as a piecewise deterministic process. Stochastic methods have previously been employed to describe various electrodynamical processes. Here, we employ an open-system time-dependent configuration interaction ansatz with a resolution-of-identity Hamiltonian to describe the motion of electrons and holes through the nanojunction subject to interaction with open boundary conditions. The absorption of charge carriers into reservoir states is described using Lindblad operators to simulate the conductance behavior in real time. Incoming charge carriers are described as bias-dependent excitations that create electron–hole pairs localized at the junction. To test the method, we use a quinone/hydroquinone nanojunction as a toy problem, exhibiting a marked change in conduction due to quantum interferences.