  Superconducting properties of a material, such as electron-electron
interactions and the critical temperature of superconducting transition can be
expressed via the effective dielectric response function of the material. Such
a description is valid on the spatial scales below the superconducting
coherence length (the size of the Cooper pair), which equals ~100 nm in a
typical BCS superconductor. Searching for natural materials exhibiting larger
electron-electron interactions constitutes a traditional approach to high
temperature superconductivity research. Here we point out that recently
developed field of electromagnetic metamaterials deals with somewhat related
task of dielectric response engineering on sub-100 nm scale. We argue that the
metamaterial approach to dielectric response engineering may considerably
increase the critical temperature of a composite superconductor-dielectric
metamaterial.
