Structure of the pairing gap from orbital nematic fluctuations

Abstract

We study superconducting instability from orbital nematic fluctuations in a minimal model consisting of the $d_{xz}$ and $d_{yz}$ orbitals, and choose model parameters which capture the typical Fermi surface geometry observed in iron-based superconductors. We solve the Eliashberg equations down to low temperatures with keeping the renormalization function and a full momentum dependence of the pairing gap. When superconductivity occurs in the tetragonal phase, we find that the pairing gap exhibits a weak momentum dependence over the Fermi surfaces. The superconducting instability occurs also inside the nematic phase. When the $d_{xz}$ orbital is occupied more than the $d_{yz}$ orbital in the nematic phase, a larger (smaller) gap is realized on the Fermi-surface parts, where the $d_{xz}$ ($d_{yz}$) orbital component is dominant, leading to a substantial momentum dependence of the pairing gap on the hole Fermi surfaces. On the other hand, the momentum dependence of the gap is weak on the electron Fermi surfaces. We also find that while the leading instability is the so-called $s_{++}$-wave symmetry, the second leading one is $d_{x^2-y^2}$-wave symmetry. In particular, these two states are nearly degenerate in the tetragonal phase whereas such quasi-degeneracy is lifted in the nematic phase and the $d_{x^2-y^2}$-wave symmetry changes to highly anisotropic $s$-wave symmetry.

arXiv comment19 pages, 8 figures

References in corpus (45)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Superconductivity in Iron Compounds
• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3
• Electronic Liquid Crystal Phases of a Doped Mott Insulator
• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Nematic order in iron superconductors - who is in the driver's seat?
• Phase Diagram and High Temperature Superconductivity at 65 K in Tuning Carrier Concentration of Single-Layer FeSe Films
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Theory of Electron Nematic Order in LaOFeAs
• Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor
• A minimal two-band model for the superconducting Fe-pnictides
• d-wave superconductivity and Pomeranchuk instability in the two-dimensional Hubbard model
• Heavily electron-doped electronic structure and isotropic superconducting gap in AxFe2Se2 (A=K,Cs)
• Ferro-Orbital Order and Strong Magnetic Anisotropy in the Parent Compounds of Iron-Pnictide Superconductors
• Orbital-driven nematicity in FeSe
• Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors
• Orbital-Ordering Induces Structural Phase Transition and the Resistivity Anomaly in Iron Pnictides
• In-plane electronic anisotropy of underdoped "122" Fe-arsenide superconductors revealed by measurements of detwinned single crystals
• Observation of incipient charge nematicity in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Using Gap Symmetry and Structure to Reveal the Pairing Mechanism in Fe-based Superconductors
• Instability toward Formation of Quasi-One-Dimensional Fermi Surface in Two-Dimensional t-J Model
• Possible Quasi-One-Dimensional Fermi Surface in La_{2-x}Sr_{x}CuO_4
• Spin Fluctuations, Interband Coupling, and Unconventional Pairing in Iron-based Superconductors
• Origin of Orthorhombic Transition, Magnetic Transition, and Shear Modulus Softening in Iron Pnictide Superconductors: Analysis based on the Orbital Fluctuation Theory
• Origin of Gap Anisotropy in Spin Fluctuation Models of the Fe-pnictides
• 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
• Superconducting gap anisotropy in monolayer FeSe thin film
• Microscopic theory of the nematic phase in Sr${}_3$Ru${}_2$O${}_7$
• Evolution of symmetry and structure of the gap in Fe-based superconductors with doping and interactions
• Highly anisotropic and two-fold symmetric superconducting gap in nematically ordered FeSe${}_{0.93}$S${}_{0.07}$
• Unconventional metamagnetic electron states in orbital band systems
• Superconductivity from orbital nematic fluctuations
• Orbital Order, Structural Transition and Superconductivity in Iron Pnictides
• Superconductivity in FeSe thin films driven by the interplay between nematic fluctuations and spin-orbit coupling
• Experimental observables near a nematic quantum critical point in the pnictide and cuprate superconductors
• Nodal gap structure in Fe-based superconductors due to the competition between orbital and spin fluctuations
• Evidence for a cos(4φ) Modulation of the Superconducting Energy Gap of Optimally Doped FeTe_{0.6}Se_{0.4} Single Crystals Using Laser Angle-Resolved Photoemission Spectroscopy
• Manipulation of gap nodes by uniaxial strain in iron-based superconductors
• Orbital fluctuation mechanism for superconductivity in iron-based compounds
• Extended Hubbard model of superconductivity driven by charge fluctuations in iron-pnictides
• Spin nematic fluctuations near a spin-density-wave phase
• A High-Tc Mechanism of Iron Pnictide Superconductivity due to Cooperation of Ferro-orbital and Antiferromagnetic Fluctuations
• Anomalous Superconducting-Gap Structure of Slightly Overdoped Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$

Cited by in corpus (8)

• Orbital Origin of Extremely Anisotropic Superconducting Gap in Nematic Phase of FeSe Superconductor
• Electron and Superconducting Properties of the AFeAs (A= Li, Na) Family Alkali-Metal Pnictides: Current Stage of the Research (mini-review)
• Suppression of superconductivity by spin fluctuations in iron-based superconductors
• The Hidden Nematic Fluctuations in the Triclinic (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 Superconductor Revealed by Ultrafast Optical Spectroscopy
• Superconducting Order Parameters in overdoped BaFe${}_{1.86}$Ni${}_{0.14}$As${}_2$ Revealed by Multiple Andreev Reflection Spectroscopy of Planar Break-Junctions
• Superconducting gap and nematic resonance at the quantum critical point observed by Raman scattering in $\mathrm{BaF}{\mathrm{e}}_2({\mathrm{As}}_{1-x}{\mathrm{P}}_x{)}_2$
• Spin-fluctuation glue disfavors high-critical temperature of superconductivity?
• Superconductivity near an Ising nematic quantum critical point in two dimensions