Impurity effects on the±s-wave state of the iron-based superconductors

2008/08/31 by Yunkyu Bang, Han-Yong Choi, Hyekyung Won · 6 citations
Materials Science · Physics and Astronomy · #Condensed matter physics #Impurity #Iron-based superconductors research #Physics #Quantum mechanics #Scattering #Superconductivity #cond-mat.str-el #cond-mat.supr-con

paper · pdf · doi:10.1103/physrevb.79.054529

published as Phys. Rev. B 79, 054529 (2009) · 5 pages, 3 figures, Revisions of Figures and their captions; references updated

arxiv created 2009/02/15 · openalex publication_date 2009/02/27 · arxiv updated 2013/05/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We studied the impurity scattering on the \ifmmode±\else\textpm\fis-wave superconductor (SC), with realistic parameters for the Fe pnictide SCs. Using the T-matrix method, generalized for the two bands, we found that the strong scattering limit of impurities forms an off-centered resonance state inside the superconducting (SC) gap, which modifies, surprisingly, the density of states (DOS) of a fully opened gap to a V-shaped DOS as if in the case of a d-wave SC. This behavior provides coherent explanations to the several conflicting experiments of the Fe-based SC: (1) the V-shaped DOS observed in photoemission and tunneling spectroscopy but with an isotropic gap; (2) the power-law behavior of the nuclear-spin-lattice relaxation rate (1/T₁\ensuremath∼T^\ensuremathα with \ensuremathα\ensuremath∼3) down to very low temperatures. We also extended the same T-matrix method to study the impurity suppression of the critical temperature T_c of the \ifmmode±\else\textpm\fis-wave pairing state. We found that both magnetic and nonmagnetic impurities suppress T_c with a rate that is practically indistinguishable from the standard d-wave case despite a possibly large difference of the positive and the negative s-wave order parameter magnitudes.

Citations

• Superfluid density and penetration depth in the iron pnictides
• As<mml:mprescripts/><mml:none/>75NMR Studies of SuperconductingLaFeAsO0.9F0.1
• Proximity of antiferromagnetism and superconductivity inLaFeAsO1−xFx: Effective Hamiltonian fromab initiostudies
• Nodeless superconducting gap in NdFeAsO_0.9F_0.1 single crystals from anisotropic penetration depth studies
• Experimental consequences of thes-wavecos(kx)cos(ky)superconductivity in the iron pnictides
• Effective Hamiltonian for FeAs-based superconductors
• Possible pairing states of the Fe-based superconductors
• A BCS-like gap in the superconductor SmFeAsO0.85F0.15
• Multiband magnetism and superconductivity in Fe-based compounds
• Theory of magnetic excitations in iron-based layered superconductors
• Observation of Fermi-surface–dependent nodeless superconducting gaps in Ba 0.6 K 0.4 Fe 2 As 2

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• Effects of single- and multi-substituted Zn ions in doped 122-type iron-based superconductors
• Robust s±-wave superconductivity against multi-impurity in iron-based superconductors
• Violation of Anderson’s Theorem for the Sign-Reversings-Wave State of Iron-Pnictide Superconductors
• Complex state induced by impurities in multiband superconductors
• Impurity-induced in-gap state andTcin sign-reversing s-wave superconductors: analysis of iron oxypnictide superconductors