Distinguishing $s^{\pm }$ and $s^{++}$ electron pairing symmetries by neutron spin resonance in superconducting NaFe${}_{0.935}$Co${}_{0.045}$As

Abstract

A determination of the superconducting (SC) electron pairing symmetry forms the basis for establishing a microscopic mechansim for superconductivity. For iron pnictide superconductors, the $s^{\pm }$-pairing symmetry theory predicts the presence of a sharp neutron spin resonance at an energy below the sum of hole and electron SC gap energies ($E\le 2\Delta$) below $T_c$. On the other hand, the $s^{++}$-pairing symmetry expects a broad spin excitation enhancement at an energy above $2\Delta$ below $T_c$. Although the resonance has been observed in iron pnictide superconductors at an energy below $2\Delta$ consistent with the $s^{\pm }$-pairing symmetry, the mode has also be interpreted as arising from the $s^{++}$-pairing symmetry with $E\ge 2\Delta$ due to its broad energy width and the large uncertainty in determining the SC gaps. Here we use inelastic neutron scattering to reveal a sharp resonance at E=7 meV in SC NaFe${}_{0.935}$Co${}_{0.045}$As ($T_c=18$ K). On warming towards $T_c$, the mode energy hardly softens while its energy width increases rapidly. By comparing with calculated spin-excitations spectra within the $s^{\pm }$ and $s^{++}$-pairing symmetries, we conclude that the ground-state resonance in NaFe${}_{0.935}$Co${}_{0.045}$As is only consistent with the $s^{\pm }$-pairing, and is inconsistent with the $s^{++}$-pairing symmetry.

arXiv comment9 pages, 8 figures. submitted to PRB

References in corpus (43)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Gap symmetry and structure of Fe-based superconductors
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Resonant Spin Excitation in the High Temperature Superconductor Ba0.6K0.4Fe2As2
• Magnetism and its microscopic origin in iron-based high-temperature superconductors
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• 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
• The Unexpected Properties of Alkali Metal Iron Selenide Superconductors
• Theory of magnetic excitations in iron-based layered superconductors
• Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2
• Spin Gap and Resonance at the Nesting Wavevector in Superconducting FeSe0.4Te0.6
• Momentum dependence of the superconducting gap in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• Neutron scattering as a probe of the Fe-pnicitide superconducting gap
• Three-dimensional Resonance in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Fe-based superconductors: an angle-resolved photoemission spectroscopy perspective
• Nature of magnetic excitations in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• The Synthesis and Characterization of LiFeAs and NaFeAs
• Structure of Neutron-Scattering Peak in both s++ wave and s+- wave states of an Iron pnictide Superconductor
• Symmetry of spin excitation spectra in the tetragonal paramagnetic and superconducting phases of 122-ferropnictides
• Control via electron count of the competition between magnetism and superconductivity in cobalt and nickel doped NaFeAs
• Neutron Scattering Resonance and the Fe-pnictide Superconducting Gap
• Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe1-xCox)2As2 iron pnictides
• One-sign order parameter in iron based superconductor
• Crossover from weak to strong pairing in unconventional superconductors
• Dispersive Spin Fluctuations in the near optimally-doped superconductor Ba(Fe1-xCox)2As2 ($x$=0.065)
• Local measurement of the superfluid density in the pnictide superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ across the superconducting dome
• Unconventional superconducting gap in NaFe${}_{0.95}$Co${}_{0.05}$As observed by angle-resolved photoemission spectroscopy
• Phase Diagram and Calorimetric Properties of NaFe${}_{1-x}$Co${}_x$As
• Effect of Fermi Surface Nesting on Resonant Spin Excitations in Ba1-xKxFe2As2
• Incommensurate magnetic excitations in superconducting LiFeAs
• Unusual Relationship between Magnetism and Superconductivity in FeTe${}_{0.5}$Se${}_{0.5}$
• Abrupt change in the energy gap of superconducting Ba1-xKxFe2As2 single crystals with hole doping
• Suppression of superconductivity by Neel-type magnetic fluctuations in the iron pnictides
• Neutron-Inelastic-Scattering Peak by Dissipationless Mechanism in the s++ -wave State in Iron-based Superconductors
• Resonance as a probe of the electron superconducting gap in BaFe1.9Ni0.1As2
• Two energy scales in the magnetic resonance spectrum of electron and hole doped pnictide superconductors
• Similar zone-center gaps in the low-energy spin-wave spectra of NaFeAs and BaFe2As2
• A weak-coupling superconductivity in the electron doped NaFe${}_{0.95}$Co${}_{0.05}$As is revealed by ARPES
• Determination of the pairing state in iron-based superconductors through neutron scattering
• Temperature dependence of the resonance and low energy spin excitations in superconducting FeTe${}_{0.6}$Se${}_{0.4}$

Cited by in corpus (37)

• Antiferromagnetic order and spin dynamics in iron-based superconductors
• Strong Interplay between Stripe Spin Fluctuations, Nematicity and Superconductivity in FeSe
• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• Critical Quadrupole Fluctuations and Collective Modes in Iron Pnictide Superconductors
• Superconducting Properties of the $s^{\pm }$-wave state: Fe-based superconductors
• Superconductivity from repulsion in LiFeAs: novel s-wave symmetry and potential time-reversal symmetry breaking
• Neutron spin resonance in a quasi-two-dimensional iron-based superconductor
• Short-range cluster spin glass near optimal superconductivity in BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Electron doping evolution of the magnetic excitations in BaFe2-xNixAs2
• Odd and even modes of neutron spin resonance in the bilayer iron-based superconductor CaKFe${}_4$As${}_4$
• Thermoelectric properties of iron-based superconductors and parent compounds
• Tracing the $s_{\pm }$-symmetry in iron pnictides by controlled disorder
• Neutron spin resonance in the 112-type iron-based superconductor
• Unconventional density waves and superconductivities in Fe-based superconductors and other strongly correlated electron systems
• Anisotropic neutron spin resonance in underdoped superconducting NaFe1-xCoxAs
• On infrared pseudogap in cuprate and pnictide high-temperature superconductors
• The upper critical field of NaFe${}_{1-x}$Co${}_x$As superconductors
• Transition from sign-reversed to sign-preserved Cooper-pairing symmetry in sulfur-doped iron selenide superconductors
• Electron doping evolution of the magnetic excitations in NaFe${}_{1-x}$Co${}_x$As
• Double magnetic resonance and spin anisotropy in Fe-based superconductors due to static and fluctuating antiferromagnetic orders
• Effect of gap anisotropy on the spin resonance peak in the superconducting state of iron-based materials
• Magneto Seebeck effect in REFeAsO (RE=rare earth) compounds: probing the magnon drag scenario
• Electron doping evolution of the neutron spin resonance in NaFe${}_{1-x}$Co${}_x$As
• Raman resonance in iron-based superconductors: The magnetic scenario
• Distinct itinerant spin-density waves and local-moment antiferromagnetism in an intermetallic ErPd${}_2$Si${}_2$ single crystal
• Weak-coupling superconductivity in a strongly correlated iron pnictide
• Phase diagram and neutron spin resonance of superconducting NaFe${}_{1-x}$Cu${}_x$As
• Self-energy driven resonance-like inelastic neutron spectrum in $s_{++}$-wave state in Fe-based superconductors
• Orbital selective neutron spin resonance in underdoped superconducting NaFe${}_{\text{0.985}}$Co${}_{\text{0.015}}$As
• Intrinsic charge dynamics in high-Tc AFeAs(O,F) superconductors
• Doping effects on electronic states in electron-doped FeSe: Impact of self-energy and vertex corrections
• Temperature and polarization dependence of low-energy magnetic fluctuations in nearly-optimal-doped NaFe${}_{0.9785}$Co${}_{0.0215}$As
• Neutron spin resonance as a probe of superconducting gap anisotropy in partially detwinned electron underdoped NaFe${}_{0.985}$Co${}_{0.015}$As
• Novel attractive pairing interaction in strongly correlated superconductors
• Preformed Cooper Pairs in a Triclinic Iron Pnictide Superconductor
• Ground and Applied-Field-Driven Magnetic States of Antiferromagnets
• Q Dependence of Magnetic Resonance Mode on FeTe${}_{0.5}$Se${}_{0.5}$ Studied by Inelastic Neutron Scattering