Abstract
We have investigated the behavior of the superconducting energy gap Δ in ultrathin films of quench condensed Bi near the superconductor-insulator (SI) transition. From electron tunneling measurements on these films, we conclude that Δ becomes very small and approaches zero at the SI transition. We studied high-sheet-resistance films with ’s as low as 0.19 K. This is a factor of 40 lower than the low-sheet-resistance film of 6.4 K.
- Received 23 April 1992
DOI:https://doi.org/10.1103/PhysRevLett.69.3567
©1992 American Physical Society