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Elsaka B, Yang X, Kästner P, Dingel K, Sick B, Lehmann P, Buhmann SY, Hillmer H. Casimir Effect in MEMS: Materials, Geometries, and Metrologies-A Review. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3393. [PMID: 39063687 PMCID: PMC11278474 DOI: 10.3390/ma17143393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/29/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024]
Abstract
Casimir force densities, i.e., force per area, become very large if two solid material surfaces come closer together to each other than 10 nm. In most cases, the forces are attractive. In some cases, they can be repulsive depending on the solid materials and the fluid medium in between. This review provides an overview of experimental and theoretical studies that have been performed and focuses on four main aspects: (i) the combinations of different materials, (ii) the considered geometries, (iii) the applied experimental measurement methodologies and (iv) a novel self-assembly methodology based on Casimir forces. Briefly reviewed is also the influence of additional parameters such as temperature, conductivity, and surface roughness. The Casimir effect opens many application possibilities in microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS), where an overview is also provided. The knowledge generation in this fascinating field requires interdisciplinary approaches to generate synergetic effects between technological fabrication metrology, theoretical simulations, the establishment of adequate models, artificial intelligence, and machine learning. Finally, multiple applications are addressed as a research roadmap.
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Affiliation(s)
- Basma Elsaka
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
| | - Xiaohui Yang
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
| | - Philipp Kästner
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
| | - Kristina Dingel
- Institute for Systems Analytics and Control (ISAC), Intelligent Embedded Systems Department, University of Kassel, Wilhelmshöher Allee 71-73, 34121 Kassel, Germany; (K.D.); (B.S.)
- Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab between Helmholtz-Zentrum für Materialien und Energie, Berlin (HZB) and the University of Kassel, 34121 Kassel, Germany
| | - Bernhard Sick
- Institute for Systems Analytics and Control (ISAC), Intelligent Embedded Systems Department, University of Kassel, Wilhelmshöher Allee 71-73, 34121 Kassel, Germany; (K.D.); (B.S.)
- Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab between Helmholtz-Zentrum für Materialien und Energie, Berlin (HZB) and the University of Kassel, 34121 Kassel, Germany
| | - Peter Lehmann
- Measurement Technology Group, Faculty of Electrical Engineering and Computer Science, University of Kassel, Wilhelmshöher Allee 71, 34121 Kassel, Germany;
- Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Stefan Yoshi Buhmann
- Institut für Physik, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany;
| | - Hartmut Hillmer
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
- Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Straße 40, 34132 Kassel, Germany
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Dantchev D. On Casimir and Helmholtz Fluctuation-Induced Forces in Micro- and Nano-Systems: Survey of Some Basic Results. ENTROPY (BASEL, SWITZERLAND) 2024; 26:499. [PMID: 38920508 PMCID: PMC11202628 DOI: 10.3390/e26060499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 06/27/2024]
Abstract
Fluctuations are omnipresent; they exist in any matter, due either to its quantum nature or to its nonzero temperature. In the current review, we briefly cover the quantum electrodynamic Casimir (QED) force as well as the critical Casimir (CC) and Helmholtz (HF) forces. In the QED case, the medium is usually a vacuum and the massless excitations are photons, while in the CC and HF cases the medium is usually a critical or correlated fluid and the fluctuations of the order parameter are the cause of the force between the macroscopic or mesoscopic bodies immersed in it. We discuss the importance of the presented results for nanotechnology, especially for devising and assembling micro- or nano-scale systems. Several important problems for nanotechnology following from the currently available experimental findings are spelled out, and possible strategies for overcoming them are sketched. Regarding the example of HF, we explicitly demonstrate that when a given integral quantity characterizing the fluid is conserved, it has an essential influence on the behavior of the corresponding fluctuation-induced force.
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Affiliation(s)
- Daniel Dantchev
- Institute of Mechanics, Bulgarian Academy of Sciences, Academic Georgy Bonchev St., Building 4, 1113 Sofia, Bulgaria;
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
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Matos GC, Souza RDME, Neto PAM, Impens F. Quantum Vacuum Sagnac Effect. PHYSICAL REVIEW LETTERS 2021; 127:270401. [PMID: 35061441 DOI: 10.1103/physrevlett.127.270401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/06/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
We report on the quantum electrodynamical analog of a Sagnac phase induced by the fast rotation of a neutral nanoparticle onto atomic waves propagating in its vicinity. The quantum vacuum Sagnac phase is a geometric Berry phase proportional to the angular velocity of rotation. The persistence of a noninertial effect into the inertial frame is also analogous to the Aharonov-Bohm effect. Here, a rotation confined to a restricted domain of space gives rise to an atomic phase even though the interferometer is at rest with respect to an inertial frame. By taking advantage of a plasmon resonance, we show that the magnitude of the induced phase can be close to the sensitivity limit of state of the art interferometers. The quantum vacuum Sagnac atomic phase is a geometric footprint of a dynamical Casimir-like effect.
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Affiliation(s)
- Guilherme C Matos
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-972, Brazil
| | | | - Paulo A Maia Neto
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-972, Brazil
| | - François Impens
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-972, Brazil
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Abstract
We give an overview of the work done during the past ten years on the Casimir interaction in electronic topological materials, our focus being solids, which possess surface or bulk electronic band structures with nontrivial topologies, which can be evinced through optical properties that are characterizable in terms of nonzero topological invariants. The examples we review are three-dimensional magnetic topological insulators, two-dimensional Chern insulators, graphene monolayers exhibiting the relativistic quantum Hall effect, and time reversal symmetry-broken Weyl semimetals, which are fascinating systems in the context of Casimir physics. Firstly, this is for the reason that they possess electromagnetic properties characterizable by axial vectors (because of time reversal symmetry breaking), and, depending on the mutual orientation of a pair of such axial vectors, two systems can experience a repulsive Casimir–Lifshitz force, even though they may be dielectrically identical. Secondly, the repulsion thus generated is potentially robust against weak disorder, as such repulsion is associated with the Hall conductivity that is topologically protected in the zero-frequency limit. Finally, the far-field low-temperature behavior of the Casimir force of such systems can provide signatures of topological quantization.
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Abstract
The formation of a submicron optical cavity on one side of a metal–insulator–metal (MIM) tunneling device induces a measurable electrical current between the two metal layers with no applied voltage. Reducing the cavity thickness increases the measured current. Eight types of tests were carried out to determine whether the output could be due to experimental artifacts. All gave negative results, supporting the conclusion that the observed electrical output is genuinely produced by the device. We interpret the results as being due to the suppression of vacuum optical modes by the optical cavity on one side of the MIM device, which upsets a balance in the injection of electrons excited by zero-point fluctuations. This interpretation is in accord with observed changes in the electrical output as other device parameters are varied. A feature of the MIM devices is their femtosecond-fast transport and scattering times for hot charge carriers. The fast capture in these devices is consistent with a model in which an energy ∆E may be accessed from zero-point fluctuations for a time ∆t, following a ∆E∆t uncertainty-principle-like relation governing the process.
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