Transport through a vibrating quantum dot: Polaronic effects

TL;DR

This paper investigates how electron-phonon interactions influence transport in a vibrating quantum dot using a Green's function approach, revealing effects like polaron formation and switching behavior.

Contribution

It combines an incomplete variational Lang-Firsov method with perturbative self-energy calculations to analyze transport across all electron-phonon coupling strengths.

Findings

Ground-state energy and spectral functions calculated

Linear conductance behavior characterized at finite density

Quantum dot can function as a molecular switch

Abstract

We present a Green's function based treatment of the effects of electron-phonon coupling on transport through a molecular quantum dot in the quantum limit. Thereby we combine an incomplete variational Lang-Firsov approach with a perturbative calculation of the electron-phonon self energy in the framework of generalised Matsubara Green functions and a Landauer-type transport description. Calculating the ground-state energy, the dot single-particle spectral function and the linear conductance at finite carrier density, we study the low-temperature transport properties of the vibrating quantum dot sandwiched between metallic leads in the whole electron-phonon coupling strength regime. We discuss corrections to the concept of an anti-adiabatic dot polaron and show how a deformable quantum dot can act as a molecular switch.