For 10 points, name this type of material with no resistance to electrical current.
Electrons can tunnel through a narrow discontinuity in one of these, even without an external voltage, according to the Josephson effect. Their coherence length and penetration depth are predicted by the Ginzburg-Landau theory. Those of type 2 transition gradually, and include layered perovskites like YBCO. A theory explaining how lattice vibrations, called phonons, and Cooper pairs work together to carry current in these materials is called BCS theory. When this type of material is cooled below its critical temperature, it becomes perfectly diamagnetic and expels a magnetic field in the Meissner effect. For 10 points, name this type of material with no resistance to electrical current.
Electrons can tunnel through a narrow discontinuity in one of these, even without an external voltage, according to the Josephson effect.
{superconductors} or {superconductivity}