Dirac/Weyl-node-induced oscillating Casimir effect

TL;DR

This paper theoretically investigates the oscillating Casimir effect induced by Dirac/Weyl nodes in semimetals, revealing a thickness-dependent energy oscillation that could be observed experimentally in thin film materials.

Contribution

It introduces the first theoretical demonstration of the Casimir effect for relativistic electron fields in Dirac/Weyl semimetals, linking it to Dirac/Weyl nodes and realistic material parameters.

Findings

Casimir energy oscillates with film thickness due to Dirac/Weyl nodes

The effect can be observed in materials like Cd3As2 and Na3Bi

Thickness-dependent thermodynamic properties are influenced by the Casimir energy

Abstract

The Casimir effect is a quantum phenomenon induced by the zero-point energy of relativistic fields confined in a finite-size system. This effect for photon fields has been studied for a long time, while the realization of counterparts for fermion fields in Dirac/Weyl semimetals is an open question. We theoretically demonstrate the typical properties of the Casimir effect for relativistic electron fields in Dirac/Weyl semimetals and show the results from an effective Hamiltonian for realistic materials such as Cd$_3$As$_2$ and Na$_3$Bi. We find an oscillation of the Casimir energy as a function of the thickness of the thin film, which stems from the existence of Dirac/Weyl nodes in momentum space. Experimentally, such an effect can be observed in thin films of semimetals, where the thickness dependence of thermodynamic quantities is affected by the Casimir energy.