Suppression of spin-exciton state in hole overdoped iron-based superconductors

Abstract

The mechanism of Cooper pair formation in iron-based superconductors remains a controversial topic. The main question is whether spin or orbital fluctuations are responsible for the pairing mechanism. To solve this problem, a crucial clue can be obtained by examining the remarkable enhancement of magnetic neutron scattering signals appearing in a superconducting phase. The enhancement is called spin resonance for a spin fluctuation model, in which their energy is restricted below twice the superconducting gap value (2Ds), whereas larger energies are possible in other models such as an orbital fluctuation model. Here we report the doping dependence of low-energy magnetic excitation spectra in Ba1-xKxFe2As2 for 0.5<x<0.84 studied by inelastic neutron scattering. We find that the behavior of the spin resonance dramatically changes from optimum to overdoped regions. Strong resonance peaks are observed clearly below 2Ds in the optimum doping region, while they are absent in the overdoped region. Instead, there is a transfer of spectral weight from energies below 2Ds to higher energies, peaking at values of 3Ds for x = 0.84. These results suggest a reduced impact of magnetism on Cooper pair formation in the overdoped region.

20 pages, 8 figures

References in corpus (29)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Orbital Fluctuation Mediated Superconductivity in Iron Pnictides: Analysis of Five Orbital Hubbard-Holstein Model
• Resonant Spin Excitation in the High Temperature Superconductor Ba0.6K0.4Fe2As2
• Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor
• The effect of collective spin-1 excitations on electronic spectra in high-Tc superconductors
• Theory of magnetic excitations in iron-based layered superconductors
• Structural quantum criticality and superconductivity in iron-based superconductor Ba(Fe1-xCox)2As2
• Neutron scattering as a probe of the Fe-pnicitide superconducting gap
• Three-dimensional Resonance in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Observation of incipient charge nematicity in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Universal heat conduction in the iron-arsenide superconductor KFe2As2 : Evidence of a d-wave state
• Symmetry of spin excitation spectra in the tetragonal paramagnetic and superconducting phases of 122-ferropnictides
• A magnetic origin for high temperature superconductivity in iron pnictides
• Single Crystal Growth and Characterization of the Iron-Based Superconductor KFe2As2 Synthesized by KAs Flux Method
• Universality of superconducting gaps in overdoped Ba0.3K0.7Fe2As2 observed by angle-resolved photoemission spectroscopy
• On the Superconductivity of LaFe1-yCoyAsO1-xFx
• Incommensurate spin fluctuations in hole-overdoped superconductor KFe2As2
• Effect of Fermi Surface Nesting on Resonant Spin Excitations in Ba1-xKxFe2As2
• Incommensurate magnetic excitations in superconducting LiFeAs
• Orbital Order, Structural Transition and Superconductivity in Iron Pnictides
• Splitting of resonance excitations in nearly optimally doped Ba(Fe0.94Co0.06)2As2: an inelastic neutron scattering study with polarization analysis
• Neutron-Inelastic-Scattering Peak by Dissipationless Mechanism in the s++ -wave State in Iron-based Superconductors
• Evidence for exclusion of the possibility of $d$-wave superconducting-gap symmetry in Ba-doped KFe${}_2$As${}_2$
• Dispersion of the superconducting spin resonance in underdoped and antiferromagnetic Ba(Fe1-xCox)2As2
• Incommensurate magnetic fluctuations and Fermi surface topology in LiFeAs
• Magnetic anisotropy in hole-doped superconducting Ba 0.67K 0.33Fe 2As2 probed by polarized inelastic neutron scattering
• Universality of dispersive spin-resonance mode in superconducting BaFe2As2
• Anisotropy of incommensurate magnetic excitations in slightly overdoped Ba${}_{0.5}$K${}_{0.5}$Fe${}_2$As${}_2$ probed by polarized inelastic neutron scattering experiments

Cited by in corpus (13)

• Superconductivity with broken time reversal symmetry in ion irradiated Ba${}_{0.27}$K${}_{0.73}$Fe${}_2$As${}_2$ single crystals
• Odd and even modes of neutron spin resonance in the bilayer iron-based superconductor CaKFe${}_4$As${}_4$
• 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
• Superconductivity and electronic fluctuations in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ studied by Raman scattering
• Spin excitations in hole-overdoped iron-based superconductors
• Neutron Spin Resonance in the Heavily Hole-doped KFe${}_2$As${}_2$ Superconductor
• Strong Spin Resonance Mode associated with suppression of soft magnetic ordering in Hole-doped Ba1-xNaxFe2As2
• Self-energy driven resonance-like inelastic neutron spectrum in $s_{++}$-wave state in Fe-based superconductors
• Constraints on the total coupling strength to bosons in iron based superconductors
• Neutron Spin Resonance Near a Lifshitz Transition in Overdoped Ba${}_{0.4}$K${}_{0.6}$Fe${}_2$As${}_2$
• Temperature and polarization dependence of low-energy magnetic fluctuations in nearly-optimal-doped NaFe${}_{0.9785}$Co${}_{0.0215}$As
• High-energy spin fluctuation in low-$T_{\mathrm{c}}$ iron-based superconductor LaFePO${}_{0.9}$