Stochastic model of nanomechanical electron shuttles and symmetry breaking

Abstract

Nanomechanical electron shuttles can work as ratchets for radio-frequency rectification. We develop a full stochastic model of coupled shuttles, where the mechanical motion of nanopillars and the incoherent electronic tunneling are modeled by a Markov chain. In particular, the interaction of their randomness is taken into account, so that a linear master equation is constructed. Numerical solutions from our fast approximate method and analytical derivation reveal the symmetry breaking, which results in the direct current observed in earlier measurements [Phys. Rev. Lett. 105, 067204 (2010)PRLTAO0031-900710.1103/PhysRevLett.105.067204]. Additionally, the method can facilitate device simulation of more complex designs such as shuttle arrays.

Kick-induced rectified current in symmetric nano-electromechanical shuttle

“…This device is called nano-electromechanical systems (NEMS) [1,2]. In this system, a movable mesoscopic object, namely, the single-electron shuttle, begins to transport electrons one by one beyond a certain critical bias [3][4][5][6][7][8][9][10]. Here, the Coulomb energy and mechanical motion make Ohm's law invalid for the electronic conductance so that the current is not proportional to the voltage drop across the devices.…”