Double coupled electron shuttle

TL;DR

This paper investigates a nano-electromechanical system with two metallic islands, analyzing electron transport and mechanical motion under various excitations, revealing potential for amplified detection of nanoscale mechanical motion.

Contribution

It introduces a detailed analysis of a double coupled electron shuttle, exploring its nonlinear dynamics and potential for mechanically assisted electron transfer and motion detection.

Findings

Coulomb blockade observed at room temperature.

RF excitation induces nonlinear dynamics and instabilities.

System can be tuned for parametric amplification of mechanical motion.

Abstract

A nano-shuttle consisting of two metallic islands connected in series and integrated between two contacts is studied. We evaluate the electron transport through the system in the presence of a source-drain voltage with and without an RF excitation. We evaluate the response of the system in terms of the net direct current generated by the mechanical motion of the oscillators. An introduction to the charge stability diagram is given in terms of electrochemical potentials and mechanical displacements. The low capacitance of the islands allows the observation of Coulomb blockade even at room temperature. Using radio frequency excitations, the nonlinear dynamics of the system is studied. The oscillators can be tuned to unstable regions where mechanically assisted transfer of electrons can further increase the amplitude of motion, resulting of a net energy being pumped into the system. The instabilities can be exploited to parametrically amplify the response to an excitation, suggesting a practical scheme for detection of mechanical motion of nanoscale objects.