Abstract
The sample-to-sample fluctuations in the critical current of a disordered Josesphson junction are analyzed by means of a transmission-matrix formalism. If the junction becomes small compared to the superconducting coherence length, the fluctuations at T=0 become of order e/ħ, dependent only on the energy gap of the bulk superconductors and independent of junction length or mean free path. This universal limit is reached in weak links formed from point contacts or microbridges.
- Received 16 October 1991
DOI:https://doi.org/10.1103/PhysRevLett.67.3836
©1991 American Physical Society