Dependence of non-equilibrium Casimir forces on material optical properties toward chaotic motion during device actuation

Abstract

The sensitivity of nonequilibrium Casimir forces on material optical properties can have strong impact on the actuation of devices. For this purpose, we considered nonequilibrium Casimir interactions between good and poor conductors, for example, gold (Au) and highly doped silicon carbide (SiC), respectively. Indeed, for autonomous conservative systems, the bifurcation and phase portrait analysis have shown that the nonequilibrium Casimir forces can have signi cant impact on the stable and unstable operating regimes depending on the material optical properties. At a few micrometer separations, for systems with high conductivity materials, an increasing temperature di erence between the actuating components can enhance the stable operation range due to the reduction of the Casimir force, while for the poor conductive materials, the opposite takes place. For periodically driven dissipative systems, the Melnikov function and Poincare portrait analysis have shown that for poor conductive systems, the nonequilibrium Casimir forces lead to an increased possibility for chaotic behavior and stiction with an increasing temperature di erence between the actuating components. However, for good conducting systems, the thermal contribution to Casimir forces reduces the possibility for chaotic behavior with increasing temperature, as comparison with systems without thermal uctuations shows. Nevertheless, the positive bene t of good conductors toward increased actuation stability and reduced the chaotic behavior under nonequilibrium conditions can be easily compromised by any voltage application. Therefore, thermal, nonequilibrium Casimir forces can in uence the actuation of devices toward unstable and chaotic behavior in strong correlation with their optical properties, and associated conduction state, as well as applied electrostatic potentials.

Nonequilibrium effects in the Casimir force between two similar metallic plates kept at different temperatures

“…[18] the possibility of a nonequilibrium repulsive force was proposed. Furthermore, the nonequilibrium Casimir force was considered in connection with the effect of radiative heat transfer, noncontact friction [19][20][21][22], and actuation of microdevices [23].…”

Chaotic motion due to lateral Casimir forces during nonlinear actuation dynamics

“…This theory describes the attractive interaction due to quantum fluctuations for all separations covering both the Casimir (long-range) and van der Waals (shortrange) regimes. [1][2][3][4][5][14][15][16][17] Besides the optical properties [18][19][20][21][22][23][24][25][26][27][28][29][30] and thermal contributions, [31][32][33][34][35] by engineering the boundary surface between interacting components, it is feasible to tailor the direction and strength of the Casimir force and consequently drive the actuation dynamic of NEMS/MEMS in a multitude of different ways.…”

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

“…In terms of the Lifshitz theory [9,10], the van der Waals and Casimir forces are the short-and long-range asymptotic limits, respectively, of the same force [1][2][3][4][8][9][10][11][12][13][14]. Nevertheless, the strong dependence of the Casimir force on the material optical properties can be utilized to tune the actuation of devices by proper choice of the interacting materials [5][6][7][15][16][17][18][19]. 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].…”