Superconducting Tunnel Junction (STJ)

A Superconducting Tunnel Junction (STJ) is a device made from two superconductors separated by an extremely thin insulating layer. When cooled below their critical temperature, these superconductors exhibit zero electrical resistance and allow quantum tunneling of electrons through the insulator. This tunneling effect enables precise detection of particles, like photons or radiation, because the energy from these particles creates measurable changes in the tunneling current. STJs are highly sensitive and are used in advanced scientific instruments for applications such as astrophysics and particle detection, leveraging the unique quantum properties of superconductors to achieve exceptional accuracy.