Department of Physics, Alzahra University, Tehran 1993891167, Iran.
Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Phys Rev E. 2017 Oct;96(4-1):042215. doi: 10.1103/PhysRevE.96.042215. Epub 2017 Oct 25.
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 nonconservative system chaotic behavior can take place 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 it impossible to predict whether stiction or stable actuation will occur on a long-term basis, and it is setting limitations in the design of micronano devices operating at short-range nanoscale separations.
当物质表面之间的距离小于 200nm 时，卡西米尔力可能会导致驱动装置的混沌行为增加，具体取决于卡西米尔相互作用的强度。我们在扭转振荡器中研究了相变材料中的这些现象，其中非晶态到晶态的转变分别导致高和低卡西米尔力和扭矩状态之间的转变，而无需改变材料成分。对于保守系统，分岔曲线和庞加莱映射分析表明不存在混沌行为，但晶态（高力-扭矩状态）有利于更不稳定的行为和粘连。然而，对于非保守系统，混沌行为可能会发生，从而给粘连带来重大风险，而在晶态下这种风险更为明显。后者说明了更一般的情况，即更强的卡西米尔力和扭矩增加了混沌行为发生的可能性。这使得无法长期预测粘连或稳定驱动是否会发生，从而限制了在短程纳米级分离距离下运行的微纳器件的设计。
