Viscous AC current-driven nanomotors

TL;DR

This paper demonstrates that electronic viscosity significantly influences the operation of AC-current-driven nano-motors, with ab-initio simulations showing stable rotation within specific current parameters.

Contribution

It introduces a simple nano-motor design driven by AC current in an electron liquid, highlighting the role of electronic viscosity in its operation.

Findings

Stable rotation occurs within certain current amplitude and frequency ranges.

Outside these ranges, the diatomic exhibits chaotic or no motion.

Electronic viscosity critically affects nano-motor dynamics.

Abstract

The recent discovery that electrons in nano-scale conductors can act like a highly viscous liquid has triggered a surge of research activities investigating consequences of this surprising fact. Here we demonstrate that the electronic viscosity has an enormous influence on the operation of a prototypical AC-current-driven nano-motor. The design of this prototype consists of a diatomic molecule immersed in an otherwise homogeneous electron liquid which carries an AC current. The motion of the diatomic is determined by a subtle balance between the current-induced forces and electronic friction. By ab-initio time-dependent density-functional simulations we demonstrate that the diatomic performs a continuous rotation provided the amplitude and frequency of the imposed AC current lie within certain islands of stability. Outside these islands the nuclear motion is either chaotic or comes to a stand-still. The proposed design of the nano-motor is the conceptually simplest realization of the idea of an molecular waterwheel sandwiched between conducting leads