Hot superconductors and cold insulators

The study of the magnetic-field driven superconductor-insulator transition in thin superconducting films at low temperatures reveals an unusual insulator whose conductivity seems to approach zero at a finite temperature, while its current-voltage characteristics are bistable, indicating that the electrons decouple from the phonon system, In parallel, the superconducting state at lower magnetic fields exhibits a broad range where metallic behavior is seen down to the lowest temperatures.