Vanishing quasiparticle density in a hybrid Al/Cu/Al single-electron transistor

O.-P. Saira, Antti Kemppinen, V.F. Maisi, J.P. Pekola

Research output: Contribution to journalArticleScientificpeer-review

83 Citations (Scopus)


The achievable fidelity of many nanoelectronic devices based on superconducting aluminum is limited by either the density of residual nonequilibrium quasiparticles nqp or the density of quasiparticle states in the gap, characterized by Dynes parameter γ. We infer upper bounds nqp<0.033 μm−3 and γ<1.6×10−7from transport measurements performed on Al/Cu/Al single-electron transistors, improving previous results by an order of magnitude. Owing to efficient microwave shielding and quasiparticle relaxation, a typical number of quasiparticles in the superconducting leads is zero.
Original languageEnglish
Article number012504
JournalPhysical Review B: Condensed Matter and Materials Physics
Issue number1
Publication statusPublished - 2012
MoE publication typeA1 Journal article-refereed


  • nanoelectronics
  • superconductivity
  • quasiparticles


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