Chaotic behavior in Casimir oscillators: A case study for phase change materials

TL;DR

This study explores how Casimir forces influence chaotic dynamics in phase change material-based oscillators, revealing that stronger forces increase chaos and stiction risks, impacting micro/nano device design.

Contribution

It demonstrates the conditions under which chaotic behavior arises in Casimir oscillators with phase change materials, highlighting the effects of phase transitions on stability.

Findings

Chaotic behavior is absent in conservative systems but occurs in non-conservative systems with high Casimir forces.

Crystalline phases increase the likelihood of unstable behavior and stiction.

Stronger Casimir forces correlate with higher chaos potential, affecting device predictability.

Abstract

Casimir forces between material surfaces at close proximity of less than 200 nm can lead to increased chaotic behavior of actuating devices depending on the strength of the Casimir interaction. We investigate these phenomena for phase change materials in torsional oscillators, where the amorphous to crystalline phase transitions lead to transitions between high and low Casimir force and torque states respectively, without material compositions. For a conservative system bifurcation curve and Poincare maps analysis show the absence of chaotic behavior but with the crystalline phase (high force/torque state) favoring more unstable behavior and stiction. However, for a non-conservative system chaotic behavior can occur introducing significant risk for stiction, which is again more pronounced for the crystalline phase. The latter illustrates the more general scenario that stronger Casimir forces and torques increase the possibility for chaotic behavior. The latter is making impossible to predict whether stiction or stable actuation will occur on a long term basis, and it is setting limitations in the design of micro/nano devices operating at short range nanoscale separations.