Condensed Matter Seminars

We have carried out experiments on ultrathin superconducting cylinders, which revealed the existence of a destructive regime, the loss of superconductivity around half-integer flux quanta even in the zero temperature limit, predicted by de Gennes for doubly connected samples with a diameter smaller than zero-temperature superconducting coherence length [Y. Liu, et al., Science 294, 2332 (2001)]. More recently we have done measurements on the superconductor-normal metal (S-N) transition tuned by magnetic flux in these cylinders, and found evidence for the formation of normal bands near the S-N transition.