Unidirectional direct current in coupled nanomechanical resonators by tunable symmetry breaking

作者：Prada M^*; Platero G; Pfannkuche D

来源：Physical Review B, 2014, 89(4): 045426.

DOI：10.1103/PhysRevB.89.045426

We investigate theoretically the nonlinear dynamics of the most fundamental component of a bistable coupled oscillator. Under a weak radio frequency excitation, the resonator is parametrically tuned into self-sustained oscillatory regimes. The transfer of electrons from one contact to the other is then mechanically assisted, generating a rectified current. The direction of the rectified current is, in general, determined by the phase shift between the mechanical oscillations and the signal. However, we locate intriguing parametrical regions of unidirectional rectified current, resulting from spontaneous parity-symmetry breaking. In these regions, a dynamical symmetry breaking is induced by the nonlinear coupling of the mechanical and electrical degrees of freedom. The achieved unstable regime favors then a unidirectional response, resulting in a direct, positive electric current. When operating within the Coulomb blockade limit, the charge balance in the oscillators perturbs drastically the mechanical motion, causing large accelerations that further enhance the shuttle response. Our results suggest a practical scheme for the realization of a self-powered device in the nanoscale.

• 出版日期2014-1-27