Spontaneously Symmetry-Broken Current in Coupled Nanomechanical Shuttles

TL;DR

This paper explores how coupled nanomechanical shuttles can spontaneously generate a net current through symmetry-breaking and bistable dynamics, revealing conditions for directed transport in nanoscale systems.

Contribution

It demonstrates that symmetric double charge shuttles can produce a net current due to parametric instability and bistability, a novel mechanism for current generation in nanomechanical systems.

Findings

Net current arises near specific resonance frequencies.

Symmetry-breaking occurs due to bistable motions.

Oscillation modes are mode-locked to the applied voltage.

Abstract

We investigate the transport and the dynamical properties of tunnel-coupled double charge shuttles. The oscillation frequencies of two shuttles are mode-locked to integer multiples of the applied voltage frequency $\omega$. We show that left/right-symmetric double shuttles may generate direct net current due to bistable motions caused by parametric instability. The symmetry-broken direct current appears near $\omega =\Omega_{0}/(2j-1)$, ($j=1,2,...$), where $\Omega_{0}$ is the dressed resonance frequency of the relative motion of the two shuttles.