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Ultrathin Metallic Coatings Can Induce Quantum Levitation between Nanosurfaces

Mathias Boström, Barry W. Ninham, Iver Brevik, Clas Persson, Drew F. Parsons, and Bo E. Sernelius


Appl. Phys. Lett. 100, 253104 (2012)


There is an attractive Casimir-Lifshitz force between two silica surfaces in a liquid (bromobenze or toluene). We demonstrate that adding an ultrathin (5-50Å) metallic nanocoating to one of the surfaces results in repulsive Casimir-Lifshitz forces above a critical separation. The onset of such quantum levitation comes at decreasing separations as the film thickness decreases. Remarkably the effect of retardation can turn attraction into repulsion. From that we explain how an ultrathin metallic coating may prevent nanoelectromechanical systems from crashing together.

Quantum levitation from addition of ultrathin conducting coatings may provide a well needed revitalization of the field of MEMS and NEMS.

Fig. Model system where repulsive Casimir-Lifshitz interaction can be induced between silica surfaces in toluene when one surface has an ultrathin gold nanocoating.

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Last updated: 06/22/12