How Does a Superconductor Work?

Superconductivity occurs when electrons form "Cooper pairs" that move through a material's crystal lattice without scattering — the mechanism explained by BCS theory (Bardeen, Cooper, Schrieffer, 1957). Below a material-specific critical temperature (Tc), these paired electrons behave as a quantum condensate, encountering zero resistance. Conventional superconductors require cooling to near absolute zero (e.g., niobium-titanium at 10 K / −263°C), typically using liquid helium. High-temperature superconductors (discovered in 1986) work at warmer but still cryogenic temperatures — some above 77 K (−196°C), reachable with cheaper liquid nitrogen. Applications include MRI magnets, particle accelerators, maglev trains, and quantum computers.