Impurity Effects in Sign Reversing Fully-Gapped Superconductors: Analysis of FeAs Superconductors

Abstract

To understand the impurity effect on Tc in FeAs superconductors, we analyze a simple two-band BCS model with repulsive interband interaction. The realized fully-gapped superconducting state with sign reversal, which is predicted by spin fluctuation theories in this compound, is suppressed by impurities due to the interband hopping of Cooper pairs, if the interband impurity scattering $I^{\prime }$ is equal to the intraband one $I$. When $|I^{\prime }/I|<1$, in highly contrast, Tc is almost unchanged by strong impurity scattering since the interband scattering is almost prohibited by the multiple scattering effect. Since $|I^{\prime }/I|\sim 0.5$ is expected, the robustness of superconductivity against impurities in FeAs superconductors is naturally understood in term of the sign reversing fully-gapped state.

Some discussions have been added

References in corpus (12)

• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• LaFeAsO${}_{1-x}$F${}_x$: A low carrier density superconductor near itinerant magnetism
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Spin-singlet superconductivity with multiple gaps in PrO0.89F0.11FeAs
• A possible ground state and its electronic structure of a mother material (LaOFeAs) of new superconductors
• Spin Ordering in LaOFeAs and Its Suppression in Superconductor LaO0.89F0.11FeAs Probed by Mössbauer Spectroscopy
• On the Superconductivity of LaFe1-yCoyAsO1-xFx
• Neutron scattering study of the oxypnictide superconductor La(O,F)FeAs
• Nernst effect of the new iron-based superconductor LaO${}_{1-x}$F${}_x$FeAs

Cited by in corpus (10)

• Microwave Surface-Impedance Measurements of the Magnetic Penetration Depth in Single Crystal Ba1-xKxFe2As2 Superconductors: Evidence for a Disorder-Dependent Superfluid Density
• Lifting of nodes by disorder in extended-$s$ state superconductors: application to ferropnictides
• Impurity-induced in-gap state and Tc in sign-reversing s-wave superconductors: analysis of iron oxypnictide superconductors
• Theory of Raman response in a superconductor with extended s-wave symmetry: Application to Fe-pnictides
• Perturbation Theory of High-Tc Superconductivity in Iron Pnictides
• Single Impurity Effects in Multiband Superconductors with Different Sign Order Parameters
• Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductors
• Surface Bound States in n-band Systems with Quasiclassical Approach
• Normal State Spin Dynamics of Five-band Model for Iron-pnictides
• Conventional Superconductivity in Fe-Based Pnictides: the Relevance of Intra-Band Electron-Boson Scattering