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arXiv:0802.0640 · Physical Review Letters

Quasiparticle Relaxation in Optically Excited High- Q Superconducting Resonators

R. Barends, J. J. A. Baselmans, S. J. C. Yates, J. R. Gao, J. Niels Hovenier, T. M. Klapwijk

Published Jun 25, 2008• 102 citations
arXivHTMLPDF

Abstract

The quasiparticle relaxation time in superconducting films has been measured as a function of temperature using the response of the complex conductivity to photon flux. For tantalum and aluminum, chosen for their difference in electron-phonon coupling strength, we find that at high temperatures the relaxation time increases with decreasing temperature, as expected for electron-phonon interaction. At low temperatures we find in both superconducting materials a saturation of the relaxation time, suggesting the presence of a second relaxation channel not due to electron-phonon interaction.

DOI
10.1103/physrevlett.100.257002

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The quasiparticle relaxation time in superconducting films has been measured as a function of temperature using the response of the complex conductivity to photon flux. For tantalum and aluminum, chosen for their difference in electron-phonon coupling strength, we find that at high temperatures the relaxation time increases with decreasing temperature, as expected for electron-phonon interaction. At low temperatures we find in both superconducting materials a saturation of the relaxation time, suggesting the presence of a second relaxation channel not due to electron-phonon interaction.
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