Coexistence of orbital degeneracy lifting and superconductivity in iron-based superconductors

Abstract

In contrast to conventional superconducting (SC) materials, superconductivity in high-temperature superconductors (HTCs) usually emerges in the presence of other fluctuating orders with similar or higher energy scales, thus instigating debates over their relevance for the SC pairing mechanism. In iron-based superconductors (IBSCs), local orbital fluctuations have been proposed to be directly responsible for the structural phase transition and closely related to the observed giant magnetic anisotropy and electronic nematicity. However, whether superconductivity can emerge from, or even coexist with orbital fluctuations, remains unclear. Here we report the angle-resolved photoemission spectroscopy (ARPES) observation of the lifting of symmetry-protected band degeneracy, and consequently the breakdown of local tetragonal symmetry in the SC state of Li(Fe1-xCox)As. Supported by theoretical simulations, we analyse the doping and temperature dependences of this band-splitting and demonstrate an intimate connection between ferro-orbital correlations and superconductivity.

arXiv comment19 pages, 4 figures

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Cited by in corpus (21)

• Observation of two distinct $d_{xz}/d_{yz}$ band splittings in FeSe
• DMFT+NRG study of spin-orbital separation in a three-band Hund's metal
• Observation of strong electron pairing on bands without Fermi surfaces in LiFe1-xCoxAs
• Distinguishing spin-orbit coupling and nematic order in the electronic spectrum of iron-based superconductors
• Linear Response Theory for Shear Modulus $C_{66}$ and Raman Quadrupole Susceptibility: Significant Evidence for Orbital Nematic Fluctuations in Fe-Based Superconductors
• Orbital-differentiated coherence-incoherence crossover identified by photoemission spectroscopy in LiFeAs
• Competing instabilities, orbital ordering and splitting of band degeneracies from a parquet renormalization group analysis of a 4-pocket model for iron-based superconductors: application to FeSe
• ARPES measurements of the superconducting gap of Fe-based superconductors and their implications to the pairing mechanism
• Evidence for Orbital Order and its Relation to Superconductivity in FeSe0.4Te0.6
• The form and the origin of the orbital ordering in the electronic nematic phase of the Iron-based superconductors
• Revisit of the Orbital-Fluctuation-Mediated Superconductivity in LiFeAs: Nontrivial Spin-Orbit Interaction Effects on the Bandstructure and Superconducting Gap Function
• Two distinct superconducting states controlled by orientation of local wrinkles in LiFeAs
• Differentiating Hund from Mott physics in a three-band Hubbard-Hund model: Temperature dependence of spectral, transport, and thermodynamic properties
• Electronic structure properties in the nematic phases of FeSe
• Protection of all nondefective twofold degeneracies by anti-unitary symmetries in non-Hermitian systems
• Orbital Nematic Order and Interplay with Magnetism in the Two-Orbital Hubbard Model
• Evidence for a two-fold symmetric superconducting gap in a monolayer of FeSe${}_{0.5}$Te${}_{0.5}$ on a topological insulator
• Quasiparticle scattering interference in iron pnictides: A probe of the origin of nematicity
• Interplay of charge and spin fluctuations in a Hund's coupled impurity
• Direct observation of spin-orbit coupling in iron-based superconductors
• Magnetic excitations in the normal and nematic phases of iron pnictides