Intergrain Josephson Currents in Multigap Superconductors: Microscopic Origin of Low Intergrain Critical Current and Its Recovery Potential in Iron-Pnictide Materials

Yukihiro Ota, Masahiko Machida, Tomio Koyama

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

We microscopically examine the intergrain Josephson current in iron-pnictide superconductors in order to solve the puzzle of why the intergrain current is much lower than the intragrain one. The theory predicts that the intergrain Josephson current is significantly reduced by the ±s-wave symmetry when the incoherent tunneling becomes predominant and the density of states and the gap amplitude between two bands are identical. We find in such a situation that the temperature dependence of the intergrain Josephson current shows an anomalously flat curve over a wide temperature range. Finally, we suggest important points for increasing the intergrain current.

Original languageEnglish
Article number103701
Journaljournal of the physical society of japan
Volume78
Issue number10
DOIs
Publication statusPublished - 2009 Oct 1

Keywords

  • Intergrain critical current
  • Iron-pnictide superconductors
  • Josephson junctions
  • Multigap superconductors

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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