Critical surface band gap of repulsive Casimir interaction between three dimensional topological insulators at finite temperature

TL;DR

This paper extends the understanding of Casimir interactions between topological insulators by analyzing how finite temperature affects the repulsive force and critical surface gap, confirming a universal property across various conditions.

Contribution

It generalizes the calculation of Casimir forces between topological insulators to include finite temperature effects, revealing the persistence of a universal critical surface gap property.

Findings

Finite temperature depresses the repulsive peak of Casimir force.

The critical surface gap $m_c$ increases with temperature.

The universal property $m_c a \,\sim\, 1/2$ remains valid across conditions.

Abstract

We generalize the calculation of Casimir interaction between topological insulators with opposite topological magnetoelectric polarizabilities and finite surface band gaps to finite Temperature cases. We find that finite temperature quantitatively depress the repulsive peak and enlarge the critical surface gap $m_c$ for repulsive Casimir force. However the universal property $m_c a \sim 1/2$ is still valid for various oscillation strength, temperature region and topological magnetoelectric polarizabilities.