Spontaneous Symmetry Breaking in Two Coupled Nanomechanical Electron Shuttles

TL;DR

This paper demonstrates spontaneous symmetry breaking in a nanoscale system of two coupled electron shuttles, leading to a DC current driven by AC excitation, revealing novel dynamical behavior in nanomechanical-electronic systems.

Contribution

It introduces a nanoscale electron shuttle system exhibiting spontaneous symmetry breaking and current generation through dynamical effects, a novel phenomenon in nanomechanical systems.

Findings

Nonzero DC current arises from symmetry breaking.

Current appears at sub- and superharmonics of the fundamental mode.

System demonstrates dynamical symmetry breaking in nanomechanical-electronic setup.

Abstract

We present spontaneous symmetry breaking in a nanoscale version of a setup prolific in classical mechanics: two coupled nanomechanical pendulums. The two pendulums are electron shuttles fabricated as nanopillars and placed between two capacitor plates in a homogeneous electric field. Instead of being mechanically coupled through a spring they exchange electrons, i.e. they shuttle electrons from the source to the drain 'capacitor plate'. Nonzero DC current through this system by external AC excitation is caused via dynamical symmetry breaking. This symmetry-broken current appears at sub- and superharmonics of the fundamental mode of the coupled system.