Spin fluctuations and unconventional pairing in KFe${}_2$As${}_2$

Abstract

We study the relation between the spin fluctuation and superconductivity in an heavily hole doped end material KFe${}_2$As${}_2$. We construct a five orbital model by approximately unfolding the Brillouin zone of the three dimensional ten orbital model obtained from first principles calculation. By applying the random phase approximation, we obtain the spin susceptibility and solve the linearized Eliashberg equation. The incommensurate spin fluctuation observed experimentally is understood as originating from interband interactions, where the multiorbital nature of the band structure results in an electron-hole asymmetry of the incommensurability in the whole iron-based superconductor family. As for superconductivity, s-wave and d-wave pairings are found to be in close competition, where the sign change in the gap function in the former is driven by the incommensurate spin fluctuations. We raise several possible explanations for the nodes in the superconducting gap of KFe${}_2$As${}_2$ observed experimentally.

9 pages, 7 figures

References in corpus (15)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
• Spin fluctuations and superconductivity in a 3D tight-binding model for BaFe2As2
• Evidence for nodal superconductivity in LaFePO
• Exotic d-wave superconductivity in strongly hole doped K(x)Ba(1-x)Fe2As2
• Evolution of superconductivity in Fe-based systems with doping
• Symmetry of spin excitation spectra in the tetragonal paramagnetic and superconducting phases of 122-ferropnictides
• Nodal gap structure of BaFe_2(As_{1-x}P_x)_2 from angle-resolved thermal conductivity in a magnetic field
• Interplay between magnetic properties and Fermi surface nesting in iron pnictides
• Incommensurate spin fluctuations in hole-overdoped superconductor KFe2As2
• Possible three dimensional nodes in the $s\pm$ superconducting gap of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Nodes in the Gap Function of LaFePO, the Gap Function of the Fe(Se,Te) Systems, and the STM Signature of the s${}_{\pm }$ Pairing
• Pinpointing Gap Minima in Ba(Fe${}_{0.94}$Co${}_{0.06}{)}_2$As${}_2$ \textit{via} Band Structure Calculations and Electronic Raman Scattering
• Multiorbital Spin Susceptibility in a Magnetically Ordered State - Orbital versus Excitonic Spin Density Wave Scenario

Cited by in corpus (44)

• Iron-Based Superconductors: current status of materials and pairing mechanism
• Functional Renormalization Group for multi-orbital Fermi Surface Instabilities
• Using Gap Symmetry and Structure to Reveal the Pairing Mechanism in Fe-based Superconductors
• Universal heat conduction in the iron-arsenide superconductor KFe2As2 : Evidence of a d-wave state
• s+is State with Broken Time Reversal Symmetry in Fe-Based Superconductors
• Change of pairing symmetry in the iron-based superconductor KFe2As2
• Evolution of symmetry and structure of the gap in Fe-based superconductors with doping and interactions
• Leggett modes in iron-based superconductors as a probe of Time Reversal Symmetry Breaking
• Gap Symmetry in KFe_2As_2 and cos 4θgap component in LiFeAs
• Superconductivity in nickel based 112 systems
• Hund interaction, spin-orbit coupling and the mechanism of superconductivity in strongly hole-doped iron pnictides
• Abrupt change in the energy gap of superconducting Ba1-xKxFe2As2 single crystals with hole doping
• Fermi surface in KFe2As2 determined via de Haas-van Alphen oscillation measurements
• Low-Temperature and High-Energy-Resolution Laser Photoemission Spectroscopy
• Potential antiferromagnetic fluctuations in hole-doped iron-pnictide superconductor Ba_{1-x}K_{x}Fe_{2}As_{2} studied by ^{75}As nuclear magnetic
• Evidence of nematic order and nodal superconducting gap along [110] direction in RbFe2As2
• Phosphor induced significant hole-doping in ferropnictide superconductor BaFe2(As(1-x)Px)2
• Evidence for exclusion of the possibility of $d$-wave superconducting-gap symmetry in Ba-doped KFe${}_2$As${}_2$
• Shadow gap in the over-doped (Ba${}_{1-x}$K${}_x$)Fe${}_2$As${}_2$ compound
• Ground state, collective mode, phase soliton and vortex in multiband superconductors
• Evidence of d-wave Superconductivity in K_(1-x)Na_xFe_2As_2 (x = 0, 0.1) Single Crystals from Low-Temperature Specific Heat Measurements
• Multiband Superconductivity in KFe2As2: Evidence for one Isotropic and several Liliputian Energy Gaps
• Electronic phase separation in iron pnictides
• Unconventional density waves and superconductivities in Fe-based superconductors and other strongly correlated electron systems
• Microscopically derived multi-component Ginzburg-Landau theories for $s+is$ superconducting state
• Origin of the superconducting state in the collapsed tetragonal phase of KFe2As2
• Two distinct superconducting states in KFe${}_2$As${}_2$ under high pressure
• Anomalous impurity effects in the iron-based superconductor KFe${}_2$As${}_2$
• Ab initio Studies of Magnetism in the Iron Chalcogenides FeTe and FeSe
• Unconventional thermoelectric effect in superconductors that break time-reversal symmetry
• Electronic structure and de Haas-van Alphen frequencies in KFe2As2 within LDA+DMFT
• Pairing Symmetries of a Hole-Doped Extended Two-Orbital Model for the Pnictides
• Displacement and annihilation of Dirac gap-nodes in d-wave iron-based superconductors
• Structural, electronic, and dynamical properties of the tetragonal and collapsed tetragonal phases of KFe${}_2$As${}_2$
• $B_{1g}$-like pairing states in two-leg ladder iron superconductors
• Pairing Symmetry in Iron-Pnictide Superconductor KFe${}_2$As${}_2$
• Temperature-induced Change in the Fermi Surface Topology in the Spin Density Wave Phase of Sr(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Effect of electron correlations on spin excitation bandwidth in Ba${}_{0.75}$K${}_{0.25}$Fe${}_2$As${}_2$ as seen via time-of-flight inelastic neutron scattering
• Q-scan-analysis of the neutron scattering in iron-based superconductors
• The symplectic-N t-J model and s${}_{\pm }$ superconductors
• Dispersion kinks from electronic correlations in an unconventional iron-based superconductor
• Evolution of superconducting gap anisotropy in hole-doped 122 iron pnictides
• Consistent picture of the octet-nodal gap and its evolution with doping in heavily overdoped Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• Three-dimensional spin susceptibility in Ba${}_{0.75}$K${}_{0.25}$Fe${}_2$As${}_2$: Out-of-plane modulation revealed by neutron spectroscopy and theoretical modeling