Observation of Andreev reflection enhanced shot noise

P Dieleman*, H.G. Bukkems, T.M Klapwijk, M. Schicke, K.H. Gundlach

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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We have experimentally investigated the quasiparticle shot noise in NbN/MgO/NbN superconductor-insulator-superconductor tunnel junctions. The observed shot noise is significantly larger than theoretically expected. We attribute this to the occurrence of multiple Andreev reflection processes in pinholes present in the MgO barrier. This mechanism causes the current to flow in large charge quanta (Andreev clusters), with a voltage dependent average value of m approximate to 1 + 2 Delta/eV times the electron charge. Because of this charge enhancement effect, the shot noise is increased by the factor m.

Original languageEnglish
Pages (from-to)3486-3489
Number of pages4
JournalPhysical Review Letters
Issue number18
Publication statusPublished - 3-Nov-1997



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