Dynamics of a nanoscale rotor driven by single-electron tunneling

We investigate theoretically the dynamics and the charge transport properties of a rod-shaped nanoscale rotor, which is driven by a similar mechanism as the nanomechanical single-electron transistor (NEMSET). We show that a static electric potential gradient can lead to self-excitation of oscillatory or continuous rotational motion. We identify the relevant parameters of the device and study the dependence of the dynamics on these parameters. We discuss how the dynamics are related to the measured current through the device. Notably, in the oscillatory regime we find a negative differential conductance. The current-voltage characteristics can be used to infer details of the surrounding environment which is responsible for damping. Copyright (C) EPLA, 2012