Everybody knows about superconductivity, at cryogenic temperatures conductor resistance drops to zero for direct current. There is lesser known related phenomena called superinsulator where material gains infinite resistance.
Does it really block infinite high voltage? That seems to me too extreme to be true. Even the strongest insulators like telfon or fused quartz eventually breakdown under high voltage, so can these superinsulators really block infinite voltage?
To quote Wikipedia article on superinsulator:
The superinsulating state is the exact dual to the superconducting state and can be destroyed by increasing the temperature and applying an external magnetic field and voltage.
The reason for calling them superinsulators is then not because it cannot conduct at infinitely high voltage. Rather the definition of insulator here is as the material in which the excitations are localized, as opposed to a metal - a material where the excitations are extended. The two are dual, in the sense that they represent two thermodynamic phases separated by the metal-insulator transition. While in normal state the conducting excitations are electrons (more precisely the Landau quasiparticles), in the superconducting state these are Cooper pairs. It is thus natural to add prefix super- to an insulating material whose excitations are Cooper pairs.
