Direct observation of dispersive lower Hubbard band in iron-based superconductor FeSe

Abstract

Electronic correlations were long suggested not only to be responsible for the complexity of many novel materials, but also to form essential prerequisites for their intriguing properties. Electronic behavior of iron-based superconductors is far from conventional, while the reason for that is not yet understood. Here we present a combined study of the electronic spectrum in the iron-based superconductor FeSe by means of angle-resolved photoemission spectroscopy (ARPES) and dynamical mean field theory (DMFT). Both methods in unison reveal strong deviations of the spectrum from single-electron approximation for the whole 3$d$ band of iron: not only the well separated coherent and incoherent parts of the spectral weight are observed, but also a noticeable dispersion of the lower Hubbard band (LHB) is clearly present. This way we demonstrate correlations of the most puzzling intermediate coupling strength in iron superconductors.

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• Correlation-Driven Electronic Reconstruction in FeTe${}_{1-x}$Se${}_x$
• Electronic nematic states tuned by isoelectronic substitution in bulk FeSe1-xSx
• Orbital selectivity in electron correlations and superconducting pairing of iron-based superconductors
• Interplay of nematic and magnetic orders in FeSe under pressure
• Orbital-selective superconductivity in the nematic phase of FeSe
• Effect of non-local correlations on the electronic structure of LiFeAs
• Spin-excitation anisotropy in the nematic state of detwinned FeSe
• Correlation strength, Lifshitz transition and the emergence of a two- to three-dimensional crossover in FeSe under pressure
• Hund-enhanced electronic compressibility in FeSe and its correlation with T${}_c$
• Itinerant approach to magnetic neutron scattering of FeSe: effect of orbital selectivity
• The three-dimensional electronic structure of the nematic and antiferromagnetic phases of NaFeAs from detwinned ARPES measurements
• Emergent electronic structure of CaFe2As2
• FeSe and the missing electron pocket problem
• Basic electronic properties of iron selenide under variation of structural parameters
• Competing phases and orbital-selective behaviors in the two-orbital Hubbard-Holstein model
• Dispersion kinks from electronic correlations in an unconventional iron-based superconductor
• Observation of Two Cascading Screening Processes in an Iron-based Superconductor