Phonon-Induced Enhancement of the Superconducting Energy Gap
Timothy J. TredwellDepartment of Physics and Astronomy, University of Rochester, Rochester, New York 14627E. H. JacobsenDepartment of Physics and Astronomy, University of Rochester, Rochester, New York 14627
1975en
ABI
Abstract
We have observed large increases of the critical current in 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. By modifying this theory to account for phonon absorption we obtain a good agreement with our results on the phonon-induced enhancement of the critical current. We conclude that absorption of phonons of frequency $\ensuremath{\omega}<\frac{2\ensuremath{\Delta}(T)}{\ensuremath{\hbar}}$ increases the superconducting energy gap.
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