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arXiv · 1105.5039

Evidence for long-lived quasiparticles trapped in superconducting point contacts

M. Zgirski·L. Bretheau·Q. Le Masne·H. Pothier·D. Esteve·C. Urbina
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Abstract

We have observed that the supercurrent across phase-biased, highly transmitting atomic size contacts is strongly reduced within a broad phase interval around π. We attribute this effect to quasiparticle trapping in one of the discrete sub-gap Andreev bound states formed at the contact. Trapping occurs essentially when the Andreev energy is smaller than half the superconducting gap Δ, a situation in which the lifetime of trapped quasiparticles is found to exceed 100 \mus. The origin of this sharp energy threshold is presently not understood.

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M. Zgirski, L. Bretheau, Q. Le Masne, H. Pothier, D. Esteve, C. Urbina. 2011-06-06. Evidence for long-lived quasiparticles trapped in superconducting point contacts. https://doi.org/10.1103/physrevlett.106.257003

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