Theory and experiments on the effects of multiparticle tunneling in Josephson junctions (Articolo in rivista)

Type
Label
  • Theory and experiments on the effects of multiparticle tunneling in Josephson junctions (Articolo in rivista) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Alternative label
  • Ovchinnikov, YN; Pepe, GP; Marrocco, N; Kawakami, A; Ovchinnikov, AY; Barone, A (2007)
    Theory and experiments on the effects of multiparticle tunneling in Josephson junctions
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Ovchinnikov, YN; Pepe, GP; Marrocco, N; Kawakami, A; Ovchinnikov, AY; Barone, A (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 76 (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Univ Naples Federico 2, CNR, INFM Coherentia, I-80125 Naples, Italy; Univ Naples Federico 2, Dipartimento Sci Fis, I-80125 Naples, Italy; LD Landau Theoret Phys Inst, Russian Acad Sci, Moscow 117940, Russia; Kobe Adv ICT Res Ctr, Natl Inst Informat & Commun Technol, Nishi Ku, Kobe, Hyogo 65124, Japan; Russian Acad Sci, Inst Solid State Phys, Moscow 142432, Russia (literal)
Titolo
  • Theory and experiments on the effects of multiparticle tunneling in Josephson junctions (literal)
Abstract
  • The origin of hysteresis effect in the voltage region of the I-V curves of a superconducting tunnel junction near the threshold value V=(E-1+E-2)/e, where E-1 and E-2 are the energy gap values in superconductors, is discussed from both a theoretical and experimental point of view. It is shown how the actual structure of the I-V curve can be determined by multiparticle tunneling (MPT) processes. This circumstance is related to the essential role played by a large parameter (Delta/Gamma)(2/3) (Gamma and Delta being the depairing factor and the order parameter value in the superconductor, respectively), which can compensate the low barrier transparency. As a consequence, the perturbation theory in the transparency coefficient does no longer hold in such a threshold region. The competition of proximity effect in producing hysteresis in the I-V curve is also discussed. Besides the underlying physical aspects of the phenomenon, the actual structure of I-V characteristics is an issue of obvious interest for Josephson-junctions based devices. Experiments have been performed on high-quality NbN-based 6x6 mu m(2) tunnel junctions at temperatures down to 300 mK. I-V curves clearly show the presence of hysteresis at the threshold voltages corresponding to both n=1 and n=2 MPT processes in agreement with the predictions of the presented theory. (literal)
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