Nonlinear Actuation of Casimir Oscillators toward Chaos: Comparison of Topological Insulators and Metals

Fatemeh Tajik,Mehdi Sedighi,Zahra Babamahdi,George Palasantzas

doi:10.3390/universe7050123

Fatemeh Tajik, Mehdi Sedighi + Show 2 more

Open Access

https://doi.org/10.3390/universe7050123

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Abstract

In the current study, we explore the sensitivity of the actuation dynamics of electromechanical systems on novel materials, e.g., Bi2Se3, which is a well-known 3D Topological Insulator (TI), and compare their response to metallic conductors, e.g., Au, that are currently used in devices. Bifurcation and phase portraits analysis in conservative systems suggest that the strong difference between the conduction states of Bi2Se3 and Au yields sufficiently weaker Casimir force to enhance stable operation. Furthermore, for nonconservative driven systems, the Melnikov function and Poincare portrait analysis probed the occurrence of chaotic behavior leading to increased risk for stiction. It was found that the presence of the TI enhanced stable operation against chaotic behavior over a significantly wider range of operation conditions in comparison to typical metallic conductors. Therefore, the use of TIs can allow sufficient surface conductance to apply electrostatic compensation of residual contact potentials and, at the same time, to yield sufficiently weak Casimir forces favoring long-term stable actuation dynamics against chaotic behavior.

Highlights

To proceed with the analysis of the actuation dynamics, we introduced the bifurcation parameter δCas = Fm
We investigated the sensitivity of actuation dynamics of electromechanical systems on novel materials, for example, Bi2 Se3, a well-known 3D Topological Insulator (TI), and compared their response to good conductors, e.g., Au
Analysis in conservative systems using bifurcation and phase portraits suggests that the strong difference between the conduction states of Bi2 Se3 and Au yield sufficiently weaker Casimir force to enhance stable operation

Summary

Introduction

Advancement in fabrication and, manufacturing techniques of micro/nanoelectromechanical systems (MEMS/NEMS) attract strong attention from the scientific and technology point of view in various sensor technologies, accelerometers, microswitches, etc. [1,2,3,4]. Several studies have shown that strong Casimir forces exist between components made of metals due to their high absorption of conduction electrons in the infrared range, while the less conductive materials can provide weaker Casimir forces and enhance the stability of microdevices suitable for operation in harsh environments [5,6,7,15,16,17,18,19] Due to these unique properties of their surface states, topological insulator (TI) materials can potentially open a new window of opportunity for MEMS engineering [20,21,22,23,24,25]. Several recent studies have shown that a repulsive Casmir force can be achieved between two TI plates under certain conditions [23,24,25], which is promising for MEMS design and manufacturing In these devices, the Casimir force is sufficiently strong to play an inevitable role, but the actuation dynamics can abruptly change toward stiction due to the attractive forces. To date, how significant the influence of TIs on stable device actuation and long-term performance remains unexplored, it is well known that the occurrence of chaotic behavior is unavoidable by shrinking the size of devices

Optical Properties of Materials and Device Actuation

Results and Discussion

Conclusions