Orbital Fluctuation Theory in Iron Pnictides: Effects of As-Fe-As Bond Angle, Isotope Substitution, and $Z^2$-Orbital Pocket on the Superconductivity

Abstract

We study the pairing mechanism in iron pnictide superconductors based on the five-orbital Hubbard-Holstein model. Due to Fe-ion oscillations, the s-wave superconducting (SC) state without sign reversal (s_{++}-wave state) is induced by orbital fluctuations by using realistic model parameters. The virtue of the present theory is that the famous empirical relation between Tc and the As-Fe-As bond angle is automatically explained, since the electron-phonon (e-ph) coupling that creates the orbital fluctuations is the strongest when the As${}_4$-tetrahedron is regular. The negative iron isotope effect is also reproduced. In addition, the magnitude of the SC gap on hole-pockets is predicted to be rather insensitive to the corresponding d-orbital (xz/yz- or z^2-orbital), which is consistent with the recent bulk-sensitive angle-resolved photoemission spectroscopy (ARPES) measurement for (Ba,K)Fe${}_2$As${}_2$ and BaFe${}_2$(As,P)${}_2$. These obtained results indicate that the orbital-fluctuation-mediated s_{++}-wave state is a plausible candidate for iron pnictides.

arXiv comment11 pages, 10 figures, New discussions and figures had been added

References in corpus (44)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Evidence for an electron nematic phase transition in underdoped iron pnictide superconductors
• Pnictogen height as a possible switch between high-T_c nodeless and low-T_c nodal pairings in the iron based superconductors
• Orbital Fluctuation Mediated Superconductivity in Iron Pnictides: Analysis of Five Orbital Hubbard-Holstein Model
• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Pressure evolution of low-temperature crystal structure and bonding of 37 K $T_c$ FeSe superconductor
• Resonant Spin Excitation in the High Temperature Superconductor Ba0.6K0.4Fe2As2
• Anion height dependence of Tc for the Fe-based superconductor
• Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor
• Neutron Scattering from Magnetic Excitations in Bi_2 Sr_2 Ca_2 O_8+delta
• Effects of nematic fluctuations on the elastic properties of iron arsenide superconductors
• Comparison of Ab initio Low-Energy Models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe and FeTe: Electron Correlation and Covalency
• Orbital dependent superconductivity in Sr_2RuO_4
• Spin resonance in the d-wave superconductor CeCoIn5
• 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
• Line nodes in the energy gap of high-temperature superconducting BaFe_2(As_{1-x}P_x)_2 from penetration depth and thermal conductivity measurements
• Pairing due to Spin Fluctuations in Layered Organic Superconductors
• Unconventional superconductivity and antiferromagnetic quantum critical behavior in the isovalent-doped BaFe2(As1-xPx)2
• Strong-coupling theory of superconductivity in a degenerate Hubbard model
• Phase Diagram of Superconductivity on the Anisotropic Triangular Lattice Hubbard Model
• Orbital-dependent modifications of electronic structure across magneto-structural transition in BaFe2As2
• A Large Iron Isotope Effect in SmFeAsO1-xFx and Ba1-xKxFe2As2
• Spin Fluctuation-Induced Superconductivity in Organic Compounds
• Studies of Impurity-Doping Effects and NMR Measurement5s of La1111 and/or Nd 1111 Fe-Pnictide Superconductors
• Structure of Neutron-Scattering Peak in both s++ wave and s+- wave states of an Iron pnictide Superconductor
• Two types of s-wave pairing due to magnetic and orbital fluctuations in the two-dimensional 16-band d-p model for iron-based superconductors
• Inverse Iron Isotope Effect on the transition temperature of the (Ba,K)Fe2As2 superconductor
• On the Superconductivity of LaFe1-yCoyAsO1-xFx
• Suppression of the critical temperature of superconducting NdFeAs(OF) single crystals by Kondo-like defect sites induced by alpha-particle irradiation
• Phonon anomalies in pure and underdoped R{1-x}K{x}Fe{2}As{2} (R = Ba, Sr) investigated by Raman light scattering
• Low magnetization and anisotropy in the antiferromagnetic state of undoped iron pnictides
• Effects of Ru Doping on the Transport Behavior and Superconducting Transition Temperature of NdFeAsO0.89F0.11
• Effect of Nonmagnetic Impurity in Nearly Antiferromagnetic Fermi Liquid: Magnetic Correlations and Transport Phenomena
• Spin Fluctuation Induced Superconductivity Controlled by Orbital Fluctuation
• Effect of a Zn impurity on T_c and its implication to pairing symmetry in LaFeAsO${}_{1-x}$F${}_x$
• Absence of an appreciable iron isotope effect on the transition temperature of the optimally doped SmFeAsO_{1-y} superconductor
• Origin of critical-temperature enhancement of an iron-based high-T_c superconductor, LaFeAsO_{1-x}F_{x} : NMR study under high pressure
• Formation of partial energy gap below the structural phase transition and the rare-earth element substitution effect on infrared phonons in ReFeAsO (Re=La, Nd, and Sm)
• Detailed Structure of the Magnetic Excitation Spectra of YBa2Cu3Oy and Its Implication on the Physical Characteristics of the Electron System
• Isotope effect and the role of phonon in the Fe-based superconductors
• On the Magnetic Excitation Spectra of High Tc Cu Oxides up to the Energies far above the Resonance Energy

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• Self-Consistent Vertex Correction Analysis for Iron-Based Superconductors: Mechanism of Coulomb-Interaction-Driven Orbital Fluctuations
• d-wave pairing from spin fluctuations in the KxFe{2-y}Se2 superconductors
• Phase Diagram of Ba1-xKxFe2As2
• Using Gap Symmetry and Structure to Reveal the Pairing Mechanism in Fe-based Superconductors
• Origin of Orthorhombic Transition, Magnetic Transition, and Shear Modulus Softening in Iron Pnictide Superconductors: Analysis based on the Orbital Fluctuation Theory
• Strong nodeless pairing on separate electron Fermi surface sheets in (Tl, K)Fe${}_{1.78}$Se${}_2$ probed by ARPES
• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• Superconductivity suppression of Ba0.5K0.5Fe2-2xM2xAs2 single crystals by substitution of transition-metal (M = Mn, Ru, Co, Ni, Cu, and Zn)
• 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${}_2$
• Extraordinary quasiparticle scattering and bandwidth-control by dopants in iron-based superconductors
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• Low-Temperature and High-Energy-Resolution Laser Photoemission Spectroscopy
• Linear decrease of critical temperature with increasing Zn substitution in the iron-based superconductor BaFe1.89-2xZn2xCo0.11As2
• Neutron-Inelastic-Scattering Peak by Dissipationless Mechanism in the s++ -wave State in Iron-based Superconductors
• Raman scattering study of Spin-Density-Wave order and electron-phonon coupling in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• The gradual destruction of magnetism in the superconducting family NaFe(1-x)CoxAs
• Nodal gap structure in Fe-based superconductors due to the competition between orbital and spin fluctuations
• Orbital fluctuation theory in iron-based superconductors: s-wave superconductivity, structure transition, and impurity-induced nematic order
• Doping - dependent superconducting gap anisotropy in the two-dimensional 10-3-8 pnictide Ca${}_{10}$(Pt${}_3$As${}_8$)[(Fe${}_{1-x}$Pt${}_x$)${}_2$As${}_2$]${}_5$
• Structural, Magnetic and Electronic Properties of the Iron-Chalcogenide A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Cs, Rb, Tl and etc.) Superconductors
• Impurity-Induced Electronic Nematic State in Iron-Pnictide Superconductors
• Impurity states in multiband s-wave superconductors: analysis of iron pnictides
• Controlling Factors of Tc-Dome Structure in 1111-Type Iron Arsenide Superconductors
• Effect of electron-phonon interactions on orbital fluctuations in iron-based superconductors
• Phonon anomalies in some iron-telluride materials
• Effect of realistic finite-size impurities on Tc in Fe-based superconductors based on the five-orbital tight-binding model
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• Determination of the pairing state in iron-based superconductors through neutron scattering
• Competing phases and orbital-selective behaviors in the two-orbital Hubbard-Holstein model
• Orbital Symmetry and Orbital Excitations in High-$T_c$ Superconductors
• Orbital-Selective Superconductivity and the Effect of Lattice Distortion in Iron-Based Superconductors
• Phase competition in a one-dimensional three-orbital Hubbard-Holstein model
• Unconventional Superconductivity arising from Multipolar Kondo Interactions
• Strongly three-dimensional electronic structure and Fermi Surfaces of SrFe${}_2$(As${}_{0.65}$P${}_{0.35}$)${}_2$: Comparison with BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Quadrupolar charge dynamics in the nonmagnetic FeSe${}_{1-x}$S${}_x$ superconductors
• Synthesis of ErFeAsO-based superconductors by hydrogen doping method
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• Preliminary Tc calculations for iron-based superconductivity in NaFeAs, LiFeAs, FeSe and nanostructured FeSe/SrTiO3 Superconductors
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• Zigzag chain structure transition and orbital fluctuations in Ni-based superconductors
• Q-scan-analysis of the neutron scattering in iron-based superconductors
• Oriented gap opening in the magnetically ordered state of Iron-pnicitides: an impact of intrinsic unit cell doubling on the $Fe$ square lattice by $As$ atoms
• The role of orbital order in the stabilization of the $(\pi ,0)$ ordered magnetic state in a minimal two-band model for iron pnictides
• Effect of inelastic scattering on the nuclear magnetic relaxation rate 1/T1T in iron-based superconductors
• Effects of $c/a$ Anisotropy and Local Crystal Structure on Superconductivity in $A\mathrm{F}{\mathrm{e}}_2({\mathrm{As}}_{1-x}{\mathrm{P}}_x{)}_2$ ($A$=Ba${}_{1-y}$Sr${}_y$, Sr${}_{1-y}$Ca${}_y$ and Eu)
• The antiferromagnetic and phonon-mediated model of the NaFeAs, LiFeAs and FeSe superconductors
• Comment on "Orbital Order, Structural Transition and Superconductivity in Iron Pnictides" [arXiv:1010.0129] by Yanagi et al
• Structural, electronic properties and Fermi surface of ThCr2Si2-type charge-balanced KFe2AsSe phase as a parent system for a new group of "mixed" pnictide-chalcogenide superconductors
• Importance of both spin and orbital fluctuations in BaFe2(As1-xPx)2 : Evidence from superconducting gap anisotropy
• Orbital Order in Two-orbital Hubbard Model
• Fe-vacancy ordered Fe4Se5: The insulating parent phase of FeSe superconductor