Hierarchical quantum master equation approach to charge transport in molecular junctions with time-dependent molecule-lead coupling strengths

TL;DR

This paper presents a hierarchical quantum master equation method for accurately modeling time-dependent charge transport in molecular junctions, accounting for dynamic molecule-lead interactions and energy level fluctuations.

Contribution

It introduces a numerically exact approach to study time-dependent transport phenomena in molecular electronics, including varying coupling strengths and energy levels.

Findings

Time-dependent molecule-lead coupling significantly affects electronic current.

The hierarchical quantum master equation provides precise solutions for dynamic transport.

Model analysis reveals detailed influence of external fluctuations on current.

Abstract

Time-dependent currents in molecular junctions can be caused by structural fluctuations or interaction with external fields. In this publication, we demonstrate how the hierarchical quantum master equation approach can be used to study time-dependent transport in a molecular junction. This reduced density matrix methodology provides a numerically exact solution to the transport problem including time-dependent energy levels, molecule-lead coupling strengths and transitions between electronic states of the molecular bridge. Based on a representative model, the influence of a time-dependent molecule-lead coupling on the electronic current is analyzed in some detail.