Ultrathin Metallic Coatings Can Induce Quantum Levitation between Nanosurfaces

TL;DR

This paper demonstrates that ultrathin metallic coatings on silica surfaces can induce repulsive Casimir-Lifshitz forces in liquids, enabling quantum levitation and potentially preventing nanoscale device failure.

Contribution

It reveals that ultrathin metallic nanocoatings can switch Casimir-Lifshitz forces from attractive to repulsive, enabling quantum levitation at nanoscale separations.

Findings

Ultrathin metallic coatings induce repulsive forces in liquids.

Quantum levitation occurs at decreasing separations with thinner coatings.

Retardation effects can turn attraction into repulsion.

Abstract

There is an attractive Casimir-Lifshitz force between two silica surfaces in a liquid (bromobenze or toluene). We demonstrate that adding an ultrathin (5-50{\AA}) 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.