Explanation

The maximum current density that can exist in a superconductor under a certain temperature and magnetic field. When it exceeds this value, the superconductor will transformation into a normal conductor. According to BCS theory, through the interaction of electron phonon electron in superconductor, electrons with opposite momentum and spin form bound states and combine into Cooper pair. When the current density in the superconductor exceeds its critical value, the kinetic energy obtained by the Cooper pair from the external field will exceed its binding energy. At this time, the Cooper pair is no longer stable and is broken up into two normal electrons, so the superconductor transformation into a normal conductor.

Classification