Gap Symmetry and Stability Analysis in the Multi-Orbital Fe-Based Superconductors

Abstract

The iron-based superconductors allow for a zoo of possible order parameters due to their orbital degrees of freedom. These order parameters are often written in an orbital basis, as this allows to distinguish their different symmetry. Unlike in standard single-band superconductors, where electrons of the same band - and hence, energy - are paired, a general order parameter in such a multi-orbital system also contains pairing of electrons belonging to different bands. As this corresponds to pairing of electrons of different energy, such order parameters are energetically less stable. Here, we present a simple criterion for a stability analysis of the orbital part of the gap function based on the basic principle that electrons of equal energy are paired in the superconducting state. This not only allows to find the most stable states, but also to identify the terms in a (tight-binding) Hamiltonian suppressing any given superconducting state. Our approach thus allows to identify the minimal Hamiltonian necessary to compare competing instabilities.

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Cited by in corpus (27)

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• Superconductivity and Local Inversion-Symmetry Breaking
• Tailoring $T_c$ by symmetry principles: The concept of Superconducting Fitness
• Classification of multipole superconductivity in multi-orbital systems and its implications
• Spin fluctuations and superconductivity in KxFe{2-y}Se2
• Superconductivity without inversion and time-reversal symmetries
• Gap symmetry of the heavy fermion superconductor CeCu${}_2$Si${}_2$ at ambient pressure
• Significant contribution of As 4p orbitals to the low-lying electronic structure of 112-type iron-based superconductor Ca0.9La0.1FeAs2
• Correlation-enhanced odd-parity inter-orbital singlet pairing in the iron-pnictide superconductor LiFeAs
• Shadowed triplet pairings in Hund's metals with spin-orbit coupling
• Spin response and topology of a staggered Rashba superconductor
• Higher angular momentum pairings in interorbital shadowed-triplet superconductors: Application to Sr${}_2$RuO${}_4$
• Towards a quantitative description of tunneling conductance of superconductors: application to LiFeAs
• Symmetry and Gap Classification of the non-symmorphic SrPtAs
• Glide-Plane Symmetry and Superconducting Gap Structure of Iron-Based Superconductors
• The Coulomb problem in iron based superconductors
• Symmetry of superconducting pairing in non-pseudospin electron bands
• Exotic interband pairing in multiband superconductors
• Magnetic parity violation and parity-time-reversal-symmetric magnets
• Spin susceptibility of superconductors with strong spin-orbit coupling
• Anomalous Shiba states in topological iron-based superconductors
• Non-unitary multiorbital superconductivity from competing interactions in Dirac materials
• Effect of nonsymmorphic space group on correlation functions in iron-based superconductors
• Superconducting magnetoelectric effects in mesoscopic hybrid structures
• Unconventional superconducting correlations in fermionic many-body scars
• Quantum geometric magnetic monopole and two-phase superconductivity in CeRh${}_2$As${}_2$