Metamaterial Superconductors

TL;DR

This paper explores how electromagnetic metamaterials can enhance electron interactions to significantly increase the critical temperature of superconductors, demonstrated with aluminium and projected for other materials.

Contribution

It introduces a novel approach of using dielectric response engineering in metamaterials to boost superconducting transition temperatures, including experimental validation with aluminium-based metamaterials.

Findings

Metamaterial superconductor with Tc = 3.9 K achieved, three times higher than pure aluminium.

Projected Tc for MgB2-based metamaterials could reach liquid nitrogen temperature.

Estimated Tc for H2S-based metamaterials could reach approximately 250 K.

Abstract

Searching for natural materials exhibiting larger electron-electron interactions constitutes a traditional approach to high temperature superconductivity research. Very recently we pointed out that the newly developed field of electromagnetic metamaterials deals with the somewhat related task of dielectric response engineering on a sub-100 nm scale. Considerable enhancement of the electron-electron interaction may be expected in such metamaterial scenarios as in epsilon near zero (ENZ) and hyperbolic metamaterials. In both cases dielectric function may become small and negative in substantial portions of the relevant four-momentum space, leading to enhancement of the electron pairing interaction. This approach has been verified in experiments with aluminium-based metamaterials. Metamaterial superconductor with Tc = 3.9 K have been fabricated, that is three times that of pure aluminium (Tc = 1.2 K), which opens up new possibilities to considerably improve Tc of other simple superconductors. Taking advantage of the demonstrated success of this approach, the critical temperature of hypothetic niobium, MgB2 and H2S-based metamaterial superconductors is evaluated. The MgB2-based metamaterial superconductors are projected to reach the liquid nitrogen temperature range. In the case of an H2S-based metamaterial projected Tc appears to reach ~250 K.