Unusual Electronic Structure and Observation of Dispersion Kink in CeFeAsO Parent Compound of FeAs-Based Superconductors

TL;DR

This study reveals unusual electronic structures and a dispersion kink in CeFeAsO, a parent compound of Fe-based superconductors, highlighting deviations from theoretical predictions and the impact of magnetic transitions on electronic properties.

Contribution

First high-resolution ARPES measurements on CeFeAsO showing unique Fermi surface topology and a dispersion kink, advancing understanding of Fe-based superconductor parent compounds.

Findings

Observation of four hole-like Fermi surface sheets near Γ

Detection of a dispersion kink at ~25 meV

Significant change in quasiparticle scattering rate across magnetic transition

Abstract

We report the first comprehensive high-resolution angle-resolved photoemission measurements on CeFeAsO, a parent compound of FeAs-based high temperature superconductors with a mangetic/structural transition at $\sim$150 K. In the magnetic ordering state, four hole-like Fermi surface sheets are observed near $\Gamma$(0,0) and the Fermi surface near M(+/-$\pi$,+/-$\pi$) shows a tiny electron-like pocket at M surrounded by four Dirac cone-like strong spots. The unusual Fermi surface topology deviates strongly from the band structure calculations. The electronic signature of the magnetic/structural transition shows up in the dramatic change of the quasiparticle scattering rate. A dispersion kink at $\sim$ 25meV is for the first time observed in the parent compound of Fe-based superconductors.