Theoretical evidence for strong correlations and incoherent metallic state in FeSe

TLDR

The role of electronic Coulomb correlations in iron‑based superconductors remains an important open question. The study provides theoretical evidence for strong correlation effects in FeSe using dynamical mean field calculations. The authors use dynamical mean field theory to predict angle‑resolved photoemission spectra for FeSe. The calculations reveal a lower Hubbard band and orbital‑dependent mass enhancements, indicating that FeSe behaves as a bad metal and non‑Fermi liquid over a wide temperature range.

Abstract

The role of electronic Coulomb correlations in iron-based superconductors is an important open question. We provide theoretical evidence for strong correlation effects in the FeSe compound, based on dynamical mean field calculations. A lower Hubbard band is found in the spectral properties. Moreover, together with significant orbital-dependent mass enhancements, we find that the normal state is a bad metal over an extended temperature range, implying a non-Fermi liquid. Predictions for angle-resolved photoemission spectroscopy are made.