Orientation-dependent Casimir force arising from highly anisotropic crystals: application to Bi2Sr2CaCu2O8+delta

TL;DR

This paper calculates how the Casimir force varies with orientation in highly anisotropic crystals like BSCCO, revealing a significant dependence on optical axis orientation that could impact nanoscale device design.

Contribution

It introduces a generalized Lifshitz theory approach to compute orientation-dependent Casimir forces in anisotropic materials like BSCCO.

Findings

Casimir force varies by 10-20% with optical axis orientation.

Anisotropy significantly influences Casimir interactions at nanometer scales.

Force dependence on distance is characterized for practical separations.

Abstract

We calculate the Casimir interaction between parallel planar crystals of Au and the anisotropic cuprate superconductor Bi2Sr2CaCu2O8+delta (BSCCO), with BSCCO's optical axis either parallel or perpendicular to the crystal surface, using suitable generalizations of the Lifshitz theory. We find that the strong anisotropy of the BSCCO permittivity gives rise to a difference in the Casimir force between the two orientations of the optical axis, which depends on distance and is of order 10-20% at the experimentally accessible separations 10 to 5000 nm.