Ambegaokar-Baratoff relations for Josephson critical current in heterojunctions with multigap superconductors

Yukihiro Ota, Noriyuki Nakai, Hiroki Nakamura, Masahiko Machida, Daisuke Inotani, Yoji Ohashi, Tomio Koyama, Hideki Matsumoto

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

An extension of the Ambegaokar-Baratoff relation to a superconductor- insulator-superconductor (SIS) Josephson junction with multiple tunneling channels is derived. Applying the resultant relation to a SIS Josephson junction formed by an iron-based (five-band) and a single-band Bardeen-Cooper-Schrieffer (BCS) type superconductors, a theoretical bound of the Josephson critical current (I c) multiplied by the resistance of the junction (R n) is given. We reveal that such a bound is useful for identifying the pairing symmetry of iron-pnictide superconductors. One finds that if a measured value of I c R n is smaller than the bound then the symmetry is ±s wave, and otherwise s wave without any sign changes. In addition, we stress that temperature dependence of I c R n is sensitive to the difference of the gap functions from the BCS type gap formula in the above heterojunction.

Original languageEnglish
Article number214511
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume81
Issue number21
DOIs
Publication statusPublished - 2010 Jun 10

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SIS (superconductors)
Critical currents
Josephson junctions
Superconducting materials
Heterojunctions
heterojunctions
critical current
iron
Group 5A compounds
symmetry
temperature dependence
Iron

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Ambegaokar-Baratoff relations for Josephson critical current in heterojunctions with multigap superconductors. / Ota, Yukihiro; Nakai, Noriyuki; Nakamura, Hiroki; Machida, Masahiko; Inotani, Daisuke; Ohashi, Yoji; Koyama, Tomio; Matsumoto, Hideki.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 81, No. 21, 214511, 10.06.2010.

Research output: Contribution to journalArticle

Ota, Yukihiro ; Nakai, Noriyuki ; Nakamura, Hiroki ; Machida, Masahiko ; Inotani, Daisuke ; Ohashi, Yoji ; Koyama, Tomio ; Matsumoto, Hideki. / Ambegaokar-Baratoff relations for Josephson critical current in heterojunctions with multigap superconductors. In: Physical Review B - Condensed Matter and Materials Physics. 2010 ; Vol. 81, No. 21.
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