Perturbation Theory of High-Tc Superconductivity in Iron Pnictides

Abstract

The high-transition-temperature (high-Tc) superconductivity discovered recently in iron pnictides is analyzed within a perturbation theory. Specifically, the probable pairing symmetry, the doping dependence of the transition temperature and the pairing mechanism are studied by solving the Eliashberg equation for multi-band (2- and 5-band) Hubbard models with realistic electronic structures. The effective pairing interaction is expanded perturbatively in the on-site Coulomb integrals up to third order. Our perturbative weak-coupling approach shows that sufficiently large eigenvalues of the Eliashberg equation are obtained to explain the actual high transition temperatures by taking realistic on-site Coulomb integrals in the 5-band model. Thus, unconventional (non-phonon-mediated) superconductivity is highly likely to be realized. The superconducting order parameter does not change its sign on the Fermi surfaces, but it does change between the electron and hole Fermi surfaces. Consequently, the probable pairing symmetry is always "a nodeless extended s-wave symmetry (more specifically, an s_{+-}-wave symmetry)" over the whole parameter region that we investigated. It is suggested that the 2-band model is insufficient to explain the high values of Tc.

24 pages, 9 figures

References in corpus (27)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• 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
• LiFeAs: An Intrinsic FeAs-based Superconductor with Tc = 18K
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Superconductivity and Phase Diagram in the Iron-based Arsenic-oxides ReFeAsO1-delta (Re = rare earth metal) without F-Doping
• Superconductivity in iron-based F-doped layered quaternary compound Nd[O1-xFx]FeAs
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Superconductivity at 25 K in hole doped $(L{a}_{1-x}S{r}_x)OFeAs$
• A minimal two-band model for the superconducting Fe-pnictides
• Superconductivity at 52 K in iron-based F-doped layered quaternary compound Pr[O1-xFx]FeAs
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• Iron-based layered superconductor LaO${}_{1-x}$F${}_x$FeAs: an antiferromagnetic semimetal
• Fermi surface of superconducting LaFePO determined by quantum oscillations
• Superconductivity at 53.5 K in GdFeAsO1-delta
• A possible ground state and its electronic structure of a mother material (LaOFeAs) of new superconductors
• Ab initio Derivation of Low-energy Model for Iron-Based Superconductors LaFeAsO and LaFePO
• Pseudogap and Superconductivity in Iron-Based Layered Superconductor studied by Fluctuation-Exchange Approximation
• Impurity Effects in Sign Reversing Fully-Gapped Superconductors: Analysis of FeAs Superconductors
• Magnetism and Superconductivity in the Two-Dimensional 16 Band d-p Model for Iron-Based Superconductors
• Perturbation Theory on the Superconductivity of Heavy Fermion Superconductors CeIr_{x}Co_{1-x}In_5

Cited by in corpus (4)

• Microwave Surface-Impedance Measurements of the Magnetic Penetration Depth in Single Crystal Ba1-xKxFe2As2 Superconductors: Evidence for a Disorder-Dependent Superfluid Density
• Impurity-induced in-gap state and Tc in sign-reversing s-wave superconductors: analysis of iron oxypnictide superconductors
• Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductors
• Surface Bound States in n-band Systems with Quasiclassical Approach