Using core-shell metamaterial engineering to triple the critical temperature of a superconductor

TL;DR

This paper demonstrates that engineering a core-shell metamaterial with Al2O3-coated aluminum nanoparticles can triple the critical temperature of aluminum superconductors, confirmed by IR reflectivity measurements.

Contribution

It introduces a novel ENZ core-shell metamaterial design that significantly enhances superconductor Tc, providing experimental validation for dielectric response engineering.

Findings

Tc of aluminum is tripled using the metamaterial approach

IR reflectivity confirms dielectric function modification

Explains long-standing Tc enhancement in granular aluminum

Abstract

Recent experiments have shown the viability of the metamaterial approach to dielectric response engineering for moderately enhancing the transition temperature, Tc, of a superconductor. In this report, we demonstrate the use of Al2O3-coated aluminium nanoparticles to form the recently proposed epsilon near zero (ENZ) core-shell metamaterial superconductor with a Tc that is three times that of pure aluminium. IR reflectivity measurements confirm the predicted metamaterial modification of the dielectric function thus demonstrating the efficacy of the ENZ metamaterial approach to Tc engineering. These results provide an explanation for the long known, but not understood, enhancement of the Tc of granular aluminum films.