Dissipative time-dependent quantum transport theory: quantum interference and phonon induced decoherence dynamics

TL;DR

This paper develops a time-dependent inelastic electron transport theory incorporating strong electron-phonon interactions, revealing how phonons influence quantum interference and decoherence in molecular junctions.

Contribution

It introduces a novel theoretical framework combining equations of motion with the small polaron transformation for strong electron-phonon coupling.

Findings

Quantum interference occurs in transport through quasi-degenerate states.

Electron-phonon interaction suppresses quantum interference.

Phonon scattering destroys phase coherence.

Abstract

A time-dependent inelastic electron transport theory for strong electron-phonon interaction is established via the equations of motion method combined with the small polaron transformation. In this work, the dissipation via electron-phonon coupling is taken into account in the strong coupling regime, which validates the small polaron transformation. The corresponding equations of motion are developed, which are used to study the quantum interference effect and phonon-induced decoherence dynamics in molecular junctions. Numerical studies show clearly quantum interference effect of the transport electrons through two quasi-degenerate states with different coupling to the leads. We also found that the quantum interference can be suppressed by the electron-phonon interaction where the phase coherence is destroyed by phonon scattering. This indicates the importance of electron-phonon interaction in systems with prominent quantum interference effect.