Repulsive and attractive Casimir interactions in liquids

Applied Physics Letters

Woods

Drosdoff

et al. 2012

Self Cite

Thermal effects contributing to the Casimir interaction between objects are usually small at room temperature and they are difficult to separate from quantum mechanical contributions at higher temperatures. We propose that the thermal Casimir force effect can be observed for a graphene flake suspended in a fluid between substrates at the room temperature regime. The properly chosen materials for the substrates and fluid induce a Casimir repulsion. The balance with the other forces, such as gravity and buoyancy, results in a stable temperature dependent equilibrium separation. The suspended graphene is a promising system due to its potential for observing thermal Casimir effects at room temperature.

Section: Pacs Numbers: Valid Pacs Appear Herementioning

confidence: 99%

Temperature dependent graphene suspension due to thermal Casimir interaction

Applied Physics Letters

Woods

Drosdoff

et al. 2012

Self Cite

“…It has been recently shown that Casimir forces may hamper the functioning of MEMS and NEMS devices by providing a pull-in instability [4]. The Casimir force between two objects can induce adhesion and stiction leading to failures in devices [2,[4][5][6]. Particularly, when the size of a material is under the threshold length, the influence of the loading interaction on design and manufacturing of micro and nanodevices becomes much more prominent.…”

Section: Introductionmentioning

confidence: 99%

“…There have been increasingly more products in which the integrated micro and nano-electromechanical systems (MEMS/NEMS) are crucial in today's market because they allow for improved functionality, lower costs and higher quality. With the decrease in the size of MEMS and NEMS, additional nanoscale surface forces, such as the Casimir force and the van der Waals force, should be considered [1,2], especially in the areas of micro and nano machining, fabrication, manipulation, assembly and metrology. Therefore, a fundamental understanding of the Casimir force has recently been under intense discussion in the research and technological development (RTD) communities.…”

Section: Introductionmentioning

confidence: 99%

Interaction of a graphene sheet with a ferromagnetic metal plate

Việt²,

Poklonski

et al. 2012

Phys. Rev. B

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Nanoscale surface forces such as Casimir and the van der Waals forces can have a significant influence on fabrication, handling and assembly processes as well as the performance of micro and nano devices. In this paper, the investigation and the calculation of the Casimir force between a graphene sheet and a ferromagnetic metal substrate in a vacuum are presented. The reflection coefficients of graphene are graphene-conductivity dependent, and the conductivity of graphene is described by the Kubo formalism. There is an effect of magnetic properties of the metal on the Casimir interaction. The magnetic effect plays a significant role at low temperatures or high value of chemical potential.The numerical results also demonstrate that the thickness of a metal slab has a minor influence on the Casimir force. The investigation and findings about the Casimir force in this study would lead to useful information and effective solutions for design and manufacturing of micro and nano devices, especially in the areas of micro and nano machining, fabrication, manipulation, assembly and metrology.

“…This theory allows us to calculate the van der Waals and Casimir force between two parallel semi-infinite plates using dielectric functions of objects as a function of the imaginary frequency. The interaction between two objects with arbitrary geometries such as sphere-sphere and cylinder-cylinder systems can be calculated by the proximity force approximation (PFA) [10,13]. A different heuristic approach for studying dispersion interactions derives from the multipole expansion [14].…”

Section: Introductionmentioning

confidence: 99%

“…This calculation, however, considers only the pairwise interaction between two atoms and ignores the effects induced by other atoms. Another approach is built up from the Lifshitz theory [10][11][12]. This theory allows us to calculate the van der Waals and Casimir force between two parallel semi-infinite plates using dielectric functions of objects as a function of the imaginary frequency.…”

Section: Introductionmentioning

confidence: 99%

Van der Waals interactions between graphitic nanowiggles

Woods

Journal of Applied Physics

2013

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The van der Waals interactions between two parallel graphitic nanowiggles (GNWs) are calculated using the coupled dipole method (CDM). The CDM is an efficient and accurate approach to determine such interactions explicitly by taking into account the discrete atomic structure and many-body effect. Our findings show that the van der Waals forces vary from attraction to repulsion as nanoribbons move along their lengths with respect to each other. This feature leads to a number of stable and unstable positions of the system during the movement process. These positions can be tuned by changing the length of GNW. Moreover, the influence of the thermal effect on the van der Waals interactions is also extensively investigated. This work would give good direction for both future theoretical and experimental studies.