Phonon-affected steady-state transport through molecular quantum dots

TL;DR

This paper investigates how electron-phonon interactions influence steady-state transport in molecular quantum dots, revealing polaron formation, negative differential conductance, and effects on thermoelectric properties in both equilibrium and nonequilibrium conditions.

Contribution

It introduces a comprehensive analysis of polaron effects on transport and thermoelectric behavior in vibrating molecular quantum dots, including mechanisms for negative differential conductance.

Findings

Polaron-like transient states form at the quantum dot.

Polaronic renormalization can cause negative differential conductance.

Electron-phonon interactions affect thermoelectric properties.

Abstract

We consider transport through a vibrating molecular quantum dot contacted to macroscopic leads acting as charge reservoirs. In the equilibrium and nonequilibrium regime, we study the formation of a polaron-like transient state at the quantum dot for all ratios of the dot-lead coupling to the energy of the local phonon mode. We show that the polaronic renormalization of the dot-lead coupling is a possible mechanism for negative differential conductance. Moreover, the effective dot level follows one of the lead chemical potentials to enhance resonant transport, causing novel features in the inelastic tunneling signal. In the linear response regime, we investigate the impact of the electron-phonon interaction on the thermoelectrical properties of the quantum dot device.