Fantastic Behaviour of High-T_C Superconductor Junctions: Tunable Superconductivity

Carrier injection performed in oxygen-deficient YBa₂Cu₃O_7-δ (YBCO) hetero-structure junctions exhibits tunable resistance that is entirely different from the behaviour of semiconductor devices. Tunable superconductivity in YBCO junctions, increasing over 20K in transition temperature, has achieved by using electric processes. To our knowledge, this is the first observation that intrinsic property of high T_C superconductors' superconductivity can be adjusted as tunable functional parameters of devices. The fantastic phenomenon caused by carrier injection is discussed based on a proposed charge carrier self-trapping model and BCS theory.