Crossover from weak to strong pairing in unconventional superconductors
arXiv:1012.4041 · doi:10.1103/PhysRevB.83.214520
Abstract
Superconductors are classified by their pairing mechanism and the coupling strength, measured as the ratio of the energy gap to the critical temperature, Tc. We present an extensive comparison of the gap ratios among many single- and multiband superconductors from simple metals to high-Tc cuprates and iron pnictides. Contrary to the recently suggested universality of this ratio in Fe-based superconductors, we find that the coupling in pnictides ranges from weak, near the BCS limit, to strong, as in cuprates, bridging the gap between these two extremes. Moreover, for Fe- and Cu-based materials, our analysis reveals a universal correlation between the gap ratio and Tc, which is not found in conventional superconductors and therefore supports a common unconventional pairing mechanism in both families. An important consequence of this result for ferropnictides is that the separation in energy between the excitonic spin-resonance mode and the particle-hole continuum, which determines the resonance damping, no longer appears independent of Tc.
15 pages, 3 figures, 5 tables with an exhaustive overview of the published gap and spin-resonance measurements in Fe-based superconductors. New in V3: updated references. To be published in Phys. Rev. B
References in corpus (142)
- High-temperature superconductivity in iron-based materials
- Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
- Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
- Resonant Spin Excitation in the High Temperature Superconductor Ba0.6K0.4Fe2As2
- Evidence for two superconducting energy gaps in MgB2 by point-contact spectroscopy
- Heavily electron-doped electronic structure and isotropic superconducting gap in AxFe2Se2 (A=K,Cs)
- Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor
- Fermi surface nesting induced strong pairing in iron-based superconductors
- Neutron Scattering from Magnetic Excitations in Bi_2 Sr_2 Ca_2 O_8+delta
- Synthesis and crystal growth of Cs0.8(FeSe0.98)2: a new iron-based superconductor with Tc=27K
- The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
- Superconductivity without magnetism in LiFeAs
- Direct evidence for two-band superconductivity in MgB_2 single crystals from directional point-contact spectroscopy in magnetic fields
- Scanning Tunneling Spectroscopy and Vortex Imaging in the Iron-Pnictide Superconductor BaFeCoAs
- Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2
- Evidence for Two Superconducting Gaps in
- Momentum dependence of the superconducting gap in NdFeAsO1-xFx single crystals measured by angle resolved photoemission spectroscopy
- Two energy gaps and Fermi surface 'arcs' in NbSe2
- Spin Gap and Resonance at the Nesting Wavevector in Superconducting FeSe0.4Te0.6
- Distinct Fermi Surface Topology and Nodeless Superconducting Gap in (Tl0.58Rb0.42)Fe1.72Se2 Superconductor
- Spin-singlet superconductivity with multiple gaps in PrO0.89F0.11FeAs
- Direct evidence for a multiple superconducting gap in MgB2 from high-resolution photoemission spectroscopy
- Momentum dependence of the superconducting gap in BaKFeAs
- Superconducting gap symmetry of Ba0.6K0.4Fe2As2 studied by angle-resolved photoemission spectroscopy
- Band filling and interband scattering effects in MgB: C vs Al doping
- Multiple Nodeless Superconducting Gaps in (Ba0.6K0.4)Fe2As2 Superconductor from Angle-Resolved Photoemission Spectroscopy
- Evidence for superconducting gap nodes in the zone-centered hole bands of KFe2As2 from magnetic penetration-depth measurements
- Three-dimensional Resonance in superconducting BaFeNiAs
- Probing superconducting energy gap from infrared spectroscopy on a BaKFeAs single crystal with T=37 K
- Universal relation between magnetic resonance and superconducting gap in unconventional superconductors
- Direct Observation of Non-Monotonic dx2-y2-Wave Superconducting Gap in Electron-Doped High-Tc Superconductor Pr0.89LaCe0.11CuO4
- Microwave Surface-Impedance Measurements of the Magnetic Penetration Depth in Single Crystal Ba1-xKxFe2As2 Superconductors: Evidence for a Disorder-Dependent Superfluid Density
- Static and Dynamic Magnetism in Underdoped Superconductor BaFeCoAs
- Transport properties of the new Fe-based superconductor KxFe2Se2 (Tc = 33 K)
- Definitive experimental evidence for two-band superconductivity in MgB2
- Momentum-dependence of Superconducting Gap, strong-coupling dispersion Kink, and tightly bound Cooper pairs in the high-Tc (Sr,Ba)1-x(K,Na)xFe2As2 superconductors
- Tightly-bound Cooper pair, quasiparticle kinks and clues on the pairing potential in a high Tc FeAs Superconductor
- First Order Phase Transition and Superconductivity in BaNi2As2 Single Crystals
- Strong nodeless pairing on separate electron Fermi surface sheets in (Tl, K)FeSe probed by ARPES
- Observation of Lattice and Andreev Bound States of Vortices in Ba0.6K0.4Fe2As2 Single Crystals with Scanning Tunneling Microscopy/Spectroscopy
- Penetration depth study of superconducting gap structure of 2\textit{H}-NbSe
- Anisotropic superconducting properties of single-crystalline FeSe0.5Te0.5
- Possible Multiple Gap Superconductivity with Line Nodes in Heavily Hole-Doped Superconductor KFe2As2 Studied by 75As-NQR and Specific Heat
- Momentum-resolved superconducting gap in the bulk of BaKFeAs from combined ARPES and SR measurements
- Single crystals of LnFeAsO1-xFx (Ln=La, Pr, Nd, Sm, Gd) and Ba1-xRbxFe2As2: growth, structure and superconducting properties
- Universal versus Material-Dependent Two-Gap Behaviors in the High-Tc Cuprates: Angle-Resolved Photoemission Study of La2-xSrxCuO4
- On the multi-orbital band structure and itinerant magnetism of iron-based superconductors
- Symmetry of spin excitation spectra in the tetragonal paramagnetic and superconducting phases of 122-ferropnictides
- Point-Contact Spectroscopy of Iron-Based Layered Superconductor LaOFFeAs
- Control via electron count of the competition between magnetism and superconductivity in cobalt and nickel doped NaFeAs
- Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe1-xCox)2As2 iron pnictides
- Evidence for Two Gaps and Breakdown of the Uemura Plot in BaKFeAs Single Crystals
- Two-gap superconductivity in Ba_1-xK_xFe_2As_2: A complementary study of the magnetic penetration depth by \muSR and ARPES
- Calorimetric Evidence of Multiband Superconductivity in Ba(Fe0.925Co0.075)2As2
- Spin fluctuations in LiFeAs observed by neutron scattering
- Evidence for two-gap superconductivity in (Ba,K)Fe_2As_2 by directional point contact Andreev reflection spectroscopy
- Specific heat evidence for two-gap superconductivity in ternary-iron silicide LuFeSi
- Strong-coupling superconductivity in layered nickel-based LaOFNiAs
- Universality of superconducting gaps in overdoped Ba0.3K0.7Fe2As2 observed by angle-resolved photoemission spectroscopy
- A distinct bosonic mode in an electron-doped high-transition-temperature superconductor
- Interband superconductivity: contrasts between BCS and Eliashberg theory
- Superconducting PrOs4Sb12: a thermal conductivity study
- Evidence for multiple superconducting gaps in optimally doped BaFeCoAs from infrared spectroscopy
- Enhanced superconducting gaps in the tri-layer high- cuprate BiSrCaCuO
- Local density of states and superconducting gap in the iron chalcogenide superconductor FeSeTe observed by scanning tunneling spectroscopy
- Local measurement of the superfluid density in the pnictide superconductor Ba(FeCo)As across the superconducting dome
- Nanoscale superconducting gap variations, strong coupling signatures and lack of phase separation in optimally doped BaFe1.86Co0.14As2
- Incommensurate itinerant antiferromagnetic excitations and spin resonance in the FeTeSe superconductor
- Unconventional superconducting gap in NaFeCoAs observed by angle-resolved photoemission spectroscopy
- Multigap superconductivity and strong electron-boson coupling in Fe-based superconductors: A point-contact Andreev-reflection study of Ba(Fe1-xCox)2As2 single crystals
- Scanning tunneling spectroscopy of SmFeAsO0.85: Possible evidence for d-wave order parameter symmetry
- Optical properties of the iron-arsenic superconductor BaFe1.85Co0.15As2
- Muon Spin Rotation Measurement of the Magnetic Field Penetration Depth in Ba(Fe0.93 Co0.07)2 As2 : Evidence for Multiple Superconducting Gaps
- Nodal Superconductivity with Multiple Gaps in SmFeAsOF
- Weak superconducting pairing and a single isotropic energy gap in stoichiometric LiFeAs
- Common Fermi Surface Topology and Nodeless Superconducting Gap in K0.68Fe1.79Se2 and (Tl0.45K0.34)Fe1.84Se2 Superconductors Revealed from Angle-Resolved Photoemission Spectroscopy
- As NQR and NMR studies of superconductivity and electron correlations in iron arsenide LiFeAs
- Energy Gaps and Kohn Anomalies in Elemental Superconductors
- Electron-doping evolution of the low-energy spin excitations in the iron arsenide BaFeNiAs superconductors
- Two superconducting gaps in LaFeAsO0.92F0.08 revealed by 75As nuclear quadrupole resonance
- Point-Contact Spectroscopy of the Heavy-Fermion Superconductor CeCoIn
- The superconducting gaps in LiFeAs: Joint study of specific heat and ARPES
- Electronic correlations and unusual superconducting response in the optical properties of the iron-chalcogenide FeTe0.55Se0.45
- Superconducting gap in the presence of bilayer splitting in underdoped Bi(Pb)2212
- Spin gap and magnetic resonance in superconducting BaFeNiAs
- Point contact Andreev reflection spectroscopy of superconducting energy gaps in 122-type family of iron pnictides
- Unusual Relationship between Magnetism and Superconductivity in FeTeSe
- Theory for Magnetism and Triplet Superconductivity in LiFeAs
- Coupling to spin fluctuations from conductivity scattering rates
- Evidence for two-gap nodeless superconductivity in SmFeAsOF from point-contact Andreev-reflection spectroscopy
- Anisotropic spin fluctuations and multiple superconducting gaps in hole-doped Ba_0.7K_0.3Fe_2As_2: NMR in a single crystal
- Possible two-gap superconductivity in NdFeAs(O,F) probed by point-contact Andreev-reflection spectroscopy
- 77Se NMR study of pairing symmetry and spin dynamics in KyFe2-xSe2
- Coexistence of two order parameters and a pseudogaplike feature in the iron-based superconductor LaFeAsO_(1-x)F_x
- Low-temperature magneto-thermal transport investigation of a Ni-based superconductor BaNi2As2: Evidence for fully gapped superconductivity
- Time of life as it is in LiFeAs
- Coexistence of metallicity and superconductivity in adjacent bilayers of a high-Tc superconductor
- NiX (X=pnictide, chalcogenide, or B) Based Superconductors
- The Imaginary Part of the Optical Conductivity of
- Point-contact Andreev-reflection spectroscopy in ReFeAsO_{1-x}F_x (Re = La, Sm): Possible evidence for two nodeless gaps
- The pairing state in KFe2As2 studied by measurements of the magnetic vortex lattice
- Doping Dependence of Bilayer Resonant Spin Excitations in
- Measurement of a Sign-Changing Two-Gap Superconducting Phase in Electron-Doped Ba(Fe_{1-x}Co_x)_2As_2 Single Crystals using Scanning Tunneling Spectroscopy
- Superconductivity-induced optical anomaly in an iron arsenide
- Calorimetric Evidence of Strong-Coupling Multiband Superconductivity in Fe(Te0.57Se0.43) Single Crystal
- Comparative analysis of specific heat of YNi2B2C using nodal and two-gap models
- Nodeless superconductivity in KFeSe single crystals revealed by low temperature specific heat
- Effect of magnetic field on the spin resonance in FeTe(0.5)Se(0.5) as seen via inelastic neutron scattering
- Muon-spin-spectroscopy study of the penetration depth of FeTe0.5Se0.5
- Nodeless spin triplet superconducting gap in Sr2RuO4
- Inelastic neutron scattering study on the resonance mode in an optimally doped superconductor LaFeAsOF
- Magnetic field dependence of superconducting energy gaps in YNi2B2C: Evidence of multiband superconductivity
- Dirty Superconductivity in the Electron-Doped Cuprate PCCO: a Tunneling Study
- Evidence for multiple gaps in specific heat of LiFeAs crystals
- Improvement of superconducting properties of FeSe0.5Te0.5 single crystals by Mn substitution
- Direct observation of the superconducting gap in phonon spectra
- The nodal gap component as a good candidate for the superconducting order parameter in cuprates
- Superconductivity and Field-Induced Magnetism in SrFe_1.75Co_0.25As_2
- Spin Dynamics in Cuprates: Optical Conductivity of HgBa2CuO4
- Microwave Response of V3Si Single Crystals: Evidence for Two-Gap Superconductivity
- Strong Coupling and Double Gap Density of States in Superconducting MgB2
- Superconductivity in LnFePO (Ln = La, Pr, and Nd) single crystals
- Resonance as a probe of the electron superconducting gap in BaFe1.9Ni0.1As2
- Full Gap Superconductivity in BaKFeAs Probed by Muon Spin Rotation
- Microwave Surface Impedance Measurements of LiFeAs Single Crystals
- Small anisotropy of the lower critical field and -wave two-gap feature in single crystal LiFeAs
- Weak coupling Bardeen-Cooper-Schrieffer suerconductivity in the Electron-Doped Cuprate Superconductors
- Dispersion of the superconducting spin resonance in underdoped and antiferromagnetic Ba(Fe1-xCox)2As2
- Andreev reflection and order parameter symmetry in heavy-fermion superconductors: the case of CeCoIn
- Investigation of Superconducting Gap Structure in TbFeAsOF using Point Contact Andreev Reflection
- Lower Critical Field, Anisotropy, and Two-Gap Features of LiFeAs
- Point-contact spectroscopic studies on normal and superconducting AFe_2As_2-type iron-pnictide single crystals
- Two-band BCS superconductivity in Ba(Fe0.9Co0.1)2As2
- Microscopic Study of the Superconducting State of the Iron Pnictide RbFe_2As_2
- Evidence of a universal and isotropic 2Δ/kBTC ratio in 122-type iron pnictide superconductors over a wide doping range
- Valence band and core level photoemission spectros-copy of LaFeAsOF
- Pairing state in the rutheno-cuprate superconductor RuSr2GdCu2O8: A point contact Andreev Reflection Spectroscopy study
- Bulk superconductivity and disorder in single crystals of LaFePO
- Optical absorption in the strong coupling limit of Eliashberg theory
- Nodeless two-gap superconductivity in stoichiometric iron pnictide LiFeAs
- Strong Coupling Superconductivity in Iron-Chalcogenide FeTeSe
- Multiple superconducting gap and anisotropic spin fluctuations in iron arsenides: Comparison with nickel analog
Cited by in corpus (72)
- Gap symmetry and structure of Fe-based superconductors
- Antiferromagnetic order and spin dynamics in iron-based superconductors
- Magnetism and its microscopic origin in iron-based high-temperature superconductors
- The Unexpected Properties of Alkali Metal Iron Selenide Superconductors
- High- superconductivity by mobilizing local spin singlets and possible route to higher in pressurized LaNiO
- Magnetic Resonant Mode in the Low-Energy Spin-Excitation Spectrum of Superconducting Rb2Fe4Se5 Single Crystals
- Incommensurate Spin Fluctuations in the Spin-triplet Superconductor Candidate UTe
- Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
- Enhancement of the superconducting gap by nesting in CaKFe4As4 - a new high temperature superconductor
- Reciprocal-space structure and dispersion of the magnetic resonant mode in the superconducting phase of Rb(x)Fe(2-y)Se2 single crystals
- Close relationship between superconductivity and the bosonic mode in Ba0.6K0.4Fe2As2 and Na(Fe0.975Co0.025)As
- Neutron spin resonance in a quasi-two-dimensional iron-based superconductor
- Electron doping evolution of the anisotropic spin excitations in BaFe2-xNixAs2
- Distinguishing and electron pairing symmetries by neutron spin resonance in superconducting NaFeCoAs
- Electron doping evolution of the magnetic excitations in BaFe2-xNixAs2
- Interaction-induced singular Fermi surface in a high-temperature oxypnictide superconductor
- Hydrostatic-pressure effects on the pseudogap in slightly doped YBa2Cu3O7-δ single crystals
- Prominent role of spin-orbit coupling in FeSe
- Optical conductivity of iron-based superconductors
- Robust Upward Dispersion of the Neutron Spin Resonance in the Heavy Fermion Superconductor CeYbCoIn
- Structural, Magnetic and Electronic Properties of the Iron-Chalcogenide AFeSe (A=K, Cs, Rb, Tl and etc.) Superconductors
- Comprehensive Eliashberg analysis of microwave conductivity and penetration depth of K-, Co-, and P-substituted BaFe2As2
- Electronic band structure and momentum dependence of the superconducting gap in (Ca, Na)Fe2As2 from angle-resolved photoemission spectroscopy
- Unique interplay between superconducting and ferromagnetic orders in EuRbFeAs
- Anisotropic neutron spin resonance in underdoped superconducting NaFe1-xCoxAs
- Relationship among superconductivity, pseudogap, and high-energy magnetic fluctuations in a model high-Tc superconductor from electronic Raman scattering
- Feedback of superconductivity on the magnetic excitation spectrum of UTe
- Polarized neutron scattering studies of magnetic excitations in electron-overdoped superconducting BaFeNiAs
- Magnonlike dispersion of spin resonance in Ni-doped BaFeAs
- Magic gap ratio for optimally robust fermionic condensation and its implications for high-Tc superconductivity
- Electron doping evolution of the magnetic excitations in NaFeCoAs
- Raman Scattering Study of the Lattice Dynamics of Superconducting LiFeAs
- Double magnetic resonance and spin anisotropy in Fe-based superconductors due to static and fluctuating antiferromagnetic orders
- Superconducting properties and pseudogap from preformed Cooper pairs in the triclinic (CaFePtAs)PtAs
- Fluctuation conductivity and possible pseudogap state in FeAs-based superconductor EuFeAsO(0.85)F(0.15)
- The road map toward room temperature superconductivity: manipulating different pairing channels in systems composed of multiple electronic components
- Effects of isoelectronic Ru substitution at the Fe site on the energy gaps of optimally F-doped SmFeAsO
- Electron doping evolution of the neutron spin resonance in NaFeCoAs
- Enhanced superconductivity in FeSe/SrTiO from the combination of forward scattering phonons and spin fluctuations
- Evidence for conventional superconductivity in SrPd2Ge2
- Experimental elucidation of the origin of the `double spin resonances' in Ba(FeCo)As
- Neutron spin resonance as a probe of Fermi surface nesting and superconducting gap symmetry in BaK(FeCo)As
- Observation of a neutron spin resonance in the bilayered superconductor CsCa2Fe4As4F2
- Doping dependence of the spin excitations in Fe-based superconductors Fe1+yTe1-xSex
- Spectroscopic Evidence for the Superconductivity of Elemental Metal Y under Pressure
- Temperature dependence of the resonance and low energy spin excitations in superconducting FeTeSe
- Preferred magnetic excitations in SrNaFeAs
- Estimation of intraband and interband relative coupling constants from temperature dependences of the order parameter for two-gap superconductors
- Phase diagram and neutron spin resonance of superconducting NaFeCuAs
- Constraints on the total coupling strength to bosons in iron based superconductors
- Emergence of -wave superconducting state at the edge of -wave superconductors mediated by Andreev-bound-state-driven ferromagnetic fluctuations
- Emergence of strongly correlated electronic states driven by the Andreev bound state in d-wave superconductors
- Anisotropic effect of a magnetic field on the neutron spin resonance in FeSe
- Orbital selective neutron spin resonance in underdoped superconducting NaFeCoAs
- Generation of odd-frequency surface superconductivity with spontaneous spin current due to the zero-energy Andreev bound state
- Transmittance and reflectance measurements at terahertz frequencies on a superconducting BaFe_{1.84}Co_{0.16}As_2 ultrathin film: an analysis of the optical gaps in the Co-doped BaFe_2As_2 pnictide
- THz electrodynamics of BaFeNiAs film analyzed in the framework of multiband Eliashberg theory
- Intrinsic charge dynamics in high-Tc AFeAs(O,F) superconductors
- Electron-phonon pairing mechanism: cuprates with high value of the critical temperature
- Migdal-Eliashberg theory of multi-band high-temperature superconductivity in field-effect-doped hydrogenated (111) diamond
- Features of Excess Conductivity Behavior in a Magnetic Superconductor DyYRhRuB
- Pressure induced renormalization of energy scales in the unconventional superconductor FeTe0.6Se0.4
- Optical Study of BaFeAs under pressure: Coexistence of spin-density-wave gap and superconductivity
- Friedel oscillations and chiral superconductivity in monolayer NbSe
- Temperature and polarization dependence of low-energy magnetic fluctuations in nearly-optimal-doped NaFeCoAs
- Doping evolution of the gap structure and spin-fluctuation pairing in superconductors
- Pseudogap in cuprate and organic superconductors
- Low-energy spin excitations in optimally doped CaFeCoAsF superconductor studied with inelastic neutron scattering
- Strong electron-boson coupling in the iron-based superconductor BaFe1.9Pt0.1As2 revealed by infrared spectroscopy
- THz optical response of Ba(FeNi)As films analyzed within the three-band Eliashberg s-wave model
- Disentangling Electron-Boson Interactions on the Surface of a Familiar Ferromagnet
- Superconductivity of Co-Doped CaKFe4As4 Investigated via Point-Contact Spectroscopy and London Penetration Depth Measurements