Nonlinear actuation dynamics of driven Casimir oscillators with rough surfaces

TL;DR

This paper investigates how surface roughness affects the nonlinear actuation dynamics of Casimir-driven MEMS oscillators, revealing increased chaos and stiction risks crucial for device design and experimental understanding.

Contribution

It introduces a combined analytical and numerical analysis of rough surface effects on Casimir oscillator dynamics, highlighting the role of roughness in chaos and stiction phenomena.

Findings

Surface roughness increases the initial conditions leading to chaotic motion.

Roughness significantly raises the likelihood of stiction in MEMS oscillators.

Results are relevant for MEMS device design and fundamental experiments.

Abstract

At separations below 100 nm, Casimir-Lifshitz forces strongly influence the actuation dynamics of micro-electromechanical systems (MEMS) in dry vacuum conditions. For a micron size plate oscillating near a surface, which mimics a frequently used setup in experiments with MEMS, we show that the roughness of the surfaces significantly influences the qualitative dynamics of the oscillator. Via a combination of analytical and numerical methods, it is shown that surface roughness leads to a clear increase of initial conditions associated with chaotic motion, that eventually lead to stiction between the surfaces. Since stiction leads to malfunction of MEMS oscillators, our results are of central interest for the design of microdevices. Moreover, they are of significance for fundamentally motivated experiments performed with MEMS.