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

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 $\pm$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.

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Cited by in corpus (5)

• Ambegaokar-Baratoff relations of Josephson critical current in heterojunctions with multi-gap superconductors
• C-axis critical current of a PrFeAsO0.7 single crystal
• Theory of vortex structure in Josephson junctions with multiple tunneling channels: Vortex enlargement as a probe of $\pm s$-wave superconductivity
• Probing the Order Parameter of Superconducting LiFeAs using Pb/LiFeAs and Au/LiFeAs Point-Contact Spectroscopy
• Fluxon Dynamics of a Long Josephson Junction with Two-gap Superconductors