Temperature dependence of polaronic transport through single molecules and quantum dots

TL;DR

This paper investigates how temperature affects electron transport through single molecules and quantum dots, emphasizing the role of electron-boson coupling and the lifetime of resonant levels, contrasting with traditional polaronic models.

Contribution

It introduces a model focusing on temperature-dependent transport that highlights the importance of resonant level lifetime over the polaronic crossover behavior.

Findings

Transport on resonance is mainly influenced by resonant level lifetime.

No clear crossover from coherent to incoherent transport in differential conductance.

Temperature effects are distinct from traditional polaronic conductivity models.

Abstract

Motivated by recent experiments on electric transport through single molecules and quantum dots, we investigate a model for transport that allows for significant coupling between the electrons and a boson mode isolated on the molecule or dot. We focus our attention on the temperature dependent properties of the transport. In the Holstein picture for polaronic transport in molecular crystals the temperature dependence of the conductivity exhibits a crossover from coherent (band) to incoherent (hopping) transport. Here, the temperature dependence of the differential conductance on resonance does not show such a crossover, but is mostly determined by the lifetime of the resonant level on the molecule or dot.