Shuttle Mechanism for Charge Transfer in Coulomb Blockade Nanostructures

TL;DR

This paper introduces an electron shuttle mechanism in Coulomb blockade nanostructures where charge transfer involves self-excited oscillations of a metallic cluster, leading to a current proportional to vibration frequency.

Contribution

It proposes a novel charge transfer mechanism involving self-oscillating metallic clusters in Coulomb blockade systems, supported by a simple model analysis.

Findings

Charge transfer involves self-excited cluster oscillations.

Current is proportional to the cluster vibration frequency.

Mechanism observed at sufficiently large bias voltage.

Abstract

Room-temperature Coulomb blockade of charge transport through composite nanostructures containing organic inter-links has recently been observed. A pronounced charging effect in combination with the softness of the molecular links implies that charge transfer gives rise to a significant deformation of these structures. For a simple model system containing one nanoscale metallic cluster connected by molecular links to two bulk metallic electrodes we show that self-excitation of periodic cluster oscillations in conjunction with sequential processes of cluster charging and decharging appears for a sufficiently large bias voltage. This new `electron shuttle' mechanism of discrete charge transfer gives rise to a current through the nanostructure, which is proportional to the cluster vibration frequency.