Emergence of Fully-Gapped $s_{++}$-wave and Nodal d-wave States Mediated by Orbital- and Spin-Fluctuations in Ten-Orbital Model for KFe${}_2$Se${}_2$

Abstract

We study the superconducting state in newly discovered high-Tc superconductor K${}_x$Fe${}_2$Se${}_2$ based on the ten-orbital Hubbard-Holstein model without hole-pockets. When the Coulomb interaction is large, spin-fluctuation mediated d-wave state appears due to the nesting between electron-pockets. Interestingly, the symmetry of the body-centered tetragonal structure in K${}_x$Fe${}_2$Se${}_2$ requires the existence of nodes in the d-wave gap, although fully-gapped d-wave state is realized in the case of simple tetragonal structure. In the presence of moderate electron-phonon interaction due to Fe-ion optical modes, on the other hand, orbital fluctuations give rise to the fully-gapped $s_{++}$-wave state without sign reversal. Therefore, both superconducting states are distinguishable by careful measurements of the gap structure or the impurity effect on Tc.

arXiv comment5 pages, 4 figures, to be published in Phys. Rev. B (Rapid Communication)

References in corpus (19)

• 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
• Wien2wannier: From linearized augmented plane waves to maximally localized Wannier functions
• 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
• Comparison of Ab initio Low-Energy Models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe and FeTe: Electron Correlation and Covalency
• Violation of Anderson's Theorem for Sign-Reversing s-Wave State of Iron-Pnictide Superconductors
• Spin Gap and Resonance at the Nesting Wavevector in Superconducting FeSe0.4Te0.6
• Studies of Impurity-Doping Effects and NMR Measurement5s of La1111 and/or Nd 1111 Fe-Pnictide Superconductors
• The Electron Pairing of K${}_x$Fe${}_{2-y}$Se${}_2$
• Structure of Neutron-Scattering Peak in both s++ wave and s+- wave states of an Iron pnictide Superconductor
• Orbital Fluctuation Theory in Iron Pnictides: Effects of As-Fe-As Bond Angle, Isotope Substitution, and $Z^2$-Orbital Pocket on the Superconductivity
• On the Superconductivity of LaFe1-yCoyAsO1-xFx
• Possible three dimensional nodes in the $s\pm$ superconducting gap of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Effects of Ru Doping on the Transport Behavior and Superconducting Transition Temperature of NdFeAsO0.89F0.11
• Electron-Phonon mechanism for Superconductivity in Na${}_{0.35}$CoO${}_2$: Valence-Band Suhl-Kondo effect Driven by Shear Phonons
• s-wave Superconductivity due to Suhl-Kondo Mechanism in Na${}_x$CoO${}_2\cdot y$H${}_2$O: Effect of Coulomb Interaction and Trigonal Distortion

Cited by in corpus (56)

• Gap symmetry and structure of Fe-based superconductors
• Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor
• Iron-Based Superconductors: current status of materials and pairing mechanism
• The Unexpected Properties of Alkali Metal Iron Selenide Superconductors
• Manifestations of nematic degrees of freedom in the magnetic, elastic, and superconducting properties of the iron pnictides
• Evolution of superconductivity in Fe-based systems with doping
• Inter-pocket pairing and gap symmetry in Fe-based superconductors with only electron pockets
• NMR Study in the Iron-Selenide Rb0.74Fe1.6Se2: Determination of the Superconducting Phase as Iron Vacancy-Free Rb0.3Fe2Se2
• Superconducting gap anisotropy in monolayer FeSe thin film
• Interplay between magnetism and superconductivity in iron-chalcogenide superconductors: crystal growth and characterizations
• Magnetic Resonant Mode in the Low-Energy Spin-Excitation Spectrum of Superconducting Rb2Fe4Se5 Single Crystals
• Evolution of symmetry and structure of the gap in Fe-based superconductors with doping and interactions
• New ternary ThCr2Si2-type iron-selenide superconducting materials: synthesis, properties and simulations
• Superconductivity in the iron selenide KxFe2Se2 (0 <= x <= 1)
• Enhancement of $T_c$ by disorder in underdoped iron pnictides
• Neutron-Inelastic-Scattering Peak by Dissipationless Mechanism in the s++ -wave State in Iron-based Superconductors
• Nodal gap structure in Fe-based superconductors due to the competition between orbital and spin fluctuations
• Optical conductivity of iron-based superconductors
• Spin fluctuations and superconductivity in KxFe{2-y}Se2
• Orbital fluctuation theory in iron-based superconductors: s-wave superconductivity, structure transition, and impurity-induced nematic order
• ARPES measurements of the superconducting gap of Fe-based superconductors and their implications to the pairing mechanism
• Structure of spin excitations in heavily electron-doped Li0.8Fe0.2ODFeSe superconductors
• Structural, Magnetic and Electronic Properties of the Iron-Chalcogenide A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Cs, Rb, Tl and etc.) Superconductors
• Observation of an isotropic superconducting gap at the Brillouin zone center of Tl${}_{0.63}$K${}_{0.37}$Fe${}_{1.78}$Se${}_2$
• Block Antiferromagnetism and Checkerboard Charge Ordering in Alkali-doped Iron Selenides $R$${}_{1-x}$Fe${}_{2-y}$Se${}_2$
• Unconventional density waves and superconductivities in Fe-based superconductors and other strongly correlated electron systems
• Superconductivity without hole-pocket in electron-doped FeSe: Analysis beyond the Migdal-Eliashberg formalism
• Collective modes in multiband superconductors: Raman scattering in iron selenides
• Functional renormalization group study of the pairing symmetry and pairing mechanism in iron-selenide superconductors
• Low-energy spin excitations in Li(0.8)Fe(0.2)ODFeSe superconductor studied with inelastic neutron scattering
• Spin resonance in the superconducting state of Li${}_{1-x}$Fe${}_x$ODFe${}_{1-y}$Se observed by neutron spectroscopy
• Heterostructural one-unit-cell FeSe/SrTiO3: from high-temperature superconductivity to topological states
• Study of phase diagram and superconducting states in LaFeAsO${}_{1-x}$H${}_x$ based on the multiorbital extended Hubbard model
• Effect of realistic finite-size impurities on Tc in Fe-based superconductors based on the five-orbital tight-binding model
• Vertical loop nodes in iron-based superconductors
• Non-Fermi-Liquid Transport Phenomena and Superconductivity Driven by Orbital Fluctuations in Iron Pnictides: Analysis by Fluctuation-Exchange Approximation
• Transition from sign-reversed to sign-preserved Cooper-pairing symmetry in sulfur-doped iron selenide superconductors
• Non-Fermi-Liquid-Like Behaviors and Superconductivity Driven by Orbital Fluctuations in Iron Pnictides: Analysis by Fluctuation-Exchange Approximation
• Pairing Symmetries of a Hole-Doped Extended Two-Orbital Model for the Pnictides
• Evolution of the neutron resonances in AFe2Se2
• Charge order driven by multiple-Q spin fluctuations in heavily electron-doped iron selenide superconductors
• Study of the magnetic state of K${}_{0.8}$Fe${}_{1.6}$Se${}_2$ using the five-orbital Hubbard model in the Hartree-Fock approximation
• Muon spin rotation and infrared spectroscopy study of $B{a}_{1-x}N{a}_{x}F{e}_{2}A{s}_2$
• Observation of a Hidden Hole-Like Band Approaching the Fermi Level in K-Doped Iron Selenide Superconductor
• Possible pairing symmetry in the FeSe-based superconductors determined by quasiparticle interference
• Strong enhancement of magnetic order from bulk to stretched monolayer FeSe as Hund's metals
• Doping effects on electronic states in electron-doped FeSe: Impact of self-energy and vertex corrections
• Role of Fermi surface anisotropy in the study of gap anisotropy using magnetic-field-angle dependence of thermal oscillations in AyFe2-xSe2 superconductors
• Single nonmagnetic impurity resonance in FeSe-based 122-type superconductors as a probe for pairing symmetry
• A minimum single-band model for low-energy excitations in superconducting K${}_x$Fe${}_2$Se${}_2$
• Weak Spin Fluctuation with Finite Wave Vector and Superconducting Gap Symmetry in KxFe2-ySe2: 77Se Nuclear Magnetic Resonance
• Metal-insulator transition and superconductivity in the two-orbital Hubbard-Holstein model for iron-based superconductors
• In-gap bound states induced by a single nonmagnetic impurity in sign-preserving s-wave superconductors with incipient bands
• Generalized joint density of states and its application to exploring the pairing symmetry of superconductors
• Orbital Order in Two-orbital Hubbard Model
• Pairing Symmetry and Spin Excitations of Iron Selenide Superconductors