Abstract
We have observed large increases in the critical current of Josephson junctions under 10-GHz phonon excitation. Eliashberg has predicted that absorption of microwaves in a superconducting film will increase the energy gap by creating a nonthermal quasiparticle distribution. We modify this theory for phonon absorption and calculate the increase in the critical current of a Josephson junction corresponding to the increase in the energy gap. We obtain good agreement between our data and the modified Eliashberg theory. We conclude that absorption of phonons of energy increases the superconducting energy gap.
- Received 28 July 1975
DOI:https://doi.org/10.1103/PhysRevB.13.2931
©1976 American Physical Society