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.

References in corpus (3)

• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Dynamical Mean-Field Theory within an Augmented Plane-Wave Framework: Assessing Electronic Correlations in the Iron Pnictide LaFeAsO
• Strongly Correlated Superconductivity: a plaquette Dynamical mean field theory study

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• The three-dimensional electronic structure of the nematic and antiferromagnetic phases of NaFeAs from detwinned ARPES measurements
• Basic electronic properties of iron selenide under variation of structural parameters
• FeSe and the missing electron pocket problem
• Dispersion kinks from electronic correlations in an unconventional iron-based superconductor
• Observation of Two Cascading Screening Processes in an Iron-based Superconductor