  Coulomb interaction of charges in a metamaterial may be expressed via its
effective dielectric response function. Coulomb interaction appears
considerably enhanced in artificially engineered epsilon near zero (ENZ) and
hyperbolic metamaterials. Indeed, very recently it was observed that negative
ENZ conditions enhance superconducting properties of a composite metamaterial
via enhancement of Cooper pairing. Here we demonstrate that positive ENZ
conditions enhance Coulomb repulsion of charges, leading to considerable
enhancement of the Coulomb blockade effect in such metamaterials. Similar to
high Tc cuprates, in hyperbolic metamaterials superconductivity and the Coulomb
blockade-induced charge ordering is predicted to compete with each other.
