Metamaterial Superconductors

The work discusses a strategy for improving superconductivity by engineering how a material responds to electromagnetic fields on very small (sub-100 nm) length scales using electromagnetic metamaterials. It argues that in metamaterial scenarios such as epsilon-near-zero (ENZ) and hyperbolic metamaterials, the dielectric function can become small and negative over parts of momentum space, which can enhance electron-electron interactions and thus the electron pairing interaction. The abstract states that this approach has been verified in experiments with aluminium-based metamaterials, and that metamaterial superconductors with Tc = 3.9 K were fabricated (about three times higher than pure aluminium). It then evaluates (projects) critical temperatures for hypothetical niobium, MgB2, and H2S-based metamaterial superconductors, including a projection that MgB2-based designs could reach liquid-nitrogen temperatures and that an H2S-based design could reach around 250 K.