Vibrational effects in charge transport through a molecular double quantum dot

TL;DR

This paper theoretically investigates how vibrational modes influence charge transport in a double quantum dot system, revealing effects like negative differential conductance and current suppression due to electron-phonon interactions.

Contribution

It introduces a quantum master equation approach to analyze vibrational effects in a two-site molecular system, highlighting conditions for negative differential conductance.

Findings

Electron-phonon interactions can cause negative differential conductance.

Vibrational coupling suppresses current depending on dot configuration.

Results are relevant for molecular electronics experiments.

Abstract

Recent progress in the field of molecular electronics has revealed the fundamental importance of the coupling between the electronic degrees of freedom and specific vibrational modes. Considering the examples of a molecular dimer and a carbon nanotube double quantum dot, we here theoretically investigate transport through a two-site system that is strongly coupled to a single vibrational mode. Using a quantum master equation approach, we demonstrate that, depending on the relative positions of the two dots, electron-phonon interactions can lead to negative differential conductance and suppression of the current through the system. We also discuss the experimental relevance of the presented results and possible implementations of the studied system.