Charge Transport in a Quantum Electromechanical System

TL;DR

This paper models a quantum electromechanical system with a quantum dot between electrodes, analyzing electron-vibration interactions and their impact on current flow using a quantum master equation approach.

Contribution

It introduces a detailed dynamical model of a QEMS incorporating both electronic and vibrational degrees of freedom with damping and noise effects.

Findings

Stationary current depends on bias voltage.

Coupled equations describe electron occupation and vibrational dynamics.

Damping and noise influence system behavior.

Abstract

We describe a quantum electromechanical system(QEMS) comprising a single quantum dot harmonically bound between two electrodes and facilitating a tunneling current between them. An example of such a system is a fullerene molecule between two metal electrodes [Park et al., Nature, 407, 57 (2000)]. The description is based on a quantum master equation for the density operator of the electronic and vibrational degrees of freedom and thus incorporates the dynamics of both diagonal (population) and off diagonal (coherence) terms. We derive coupled equations of motion for the electron occupation number of the dot and the vibrational degrees of freedom, including damping of the vibration and thermo-mechanical noise. This dynamical description is related to observable features of the system including the stationary current as a function of bias voltage.