Current rectification by spontaneous symmetry breaking in coupled nanomechanical shuttles

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 ω. 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 ω=Ω0/(2j-1), (j=1,2,â€), where Ω0 is the dressed resonance frequency of the relative motion of the two shuttles. © 2006 The American Physical Society.