Theory of phase transitions in nonequilibrium superconductors with allowance for phonon reabsorption
The behavior of a nonequilibrium superconductor is investigated near the point of the phase transition that takes place under the influence of optical pumping. Nonequilibrium quasiparticles are produced on account of absorption of an electromagnetic field of frequency much higher than the superconductor gap. The energy relaxation of the quasiparticles leads to production of nonequilibrium phonons whose number is determined by a parameter ..gamma.. equal to the ratio of the time of departure of the phonons from the sample and the phonon-reabsorption time. The dependence of the superconductor order parameter on the pumping is obtained and it is shown that this dependence remains doubly valued at arbitrary values of the parameter, while the critical power decreases in the ambiguity region with increasing ..gamma... Starting with an analysis of the combined system of equations for the quasiparticles and the phonons it is found that the quasiparticle distribution function depends little on ..gamma.. at the phase transition point and is close to equilibrium with a zero quasiparticle chemical potential.
- Research Organization:
- Moscow Engineering-Physics Institute
- OSTI ID:
- 7082876
- Journal Information:
- Sov. Phys. - Solid State (Engl. Transl.); (United States), Journal Name: Sov. Phys. - Solid State (Engl. Transl.); (United States) Vol. 19:10; ISSN SPSSA
- Country of Publication:
- United States
- Language:
- English
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