Casimir Force between Atomically Thin Gold Films

TL;DR

This study uses density functional theory to calculate the dielectric properties of ultrathin gold films and predicts a significant increase in Casimir-Lifshitz force compared to bulk gold, which is experimentally detectable.

Contribution

It provides the first detailed dielectric function calculations for atomically thin gold films and predicts enhanced Casimir forces based on these properties.

Findings

Enhanced Casimir-Lifshitz force up to 20% for ultrathin gold sheets

Dielectric properties approach bulk gold with increasing thickness

Predicted force corrections are detectable with current measurement accuracy

Abstract

We have used density functional theory to calculate the anisotropic dielectric functions for ultrathin gold sheets (composed of 1, 3, 6, and 15 atomic layers). Such films are important components in nano-electromechanical systems. When using correct dielectric functions rather than bulk gold dielectric functions we predict an enhanced attractive Casimir-Lifshitz force (at most around 20%) between two atomically thin gold sheets. For thicker sheets the dielectric properties and the corresponding Casimir forces approach those of gold half-spaces. The magnitude of the corrections that we predict should, within the today's level of accuracy in Casimir force measurements, be clearly detectable.