Evidence of the influence of magnetism on pseudogap states in the high resolution spectra of EuFe$_2$As$_2$

TL;DR

This study uses high-resolution photoemission spectroscopy to explore how magnetism influences pseudogap states in EuFe$_2$As$_2$, revealing a link between magnetic order and electronic structure changes.

Contribution

It provides new evidence of the influence of antiferromagnetic order on pseudogap states in EuFe$_2$As$_2$ using advanced spectroscopic techniques.

Findings

Identification of a weakly dispersing As 4$p$ feature around 80 meV

Observation of the suppression of this feature below 20 K due to antiferromagnetic order

Detection of spin density wave transition induced band folding

Abstract

Employing {\it state of the art} high resolution photoemission spectroscopy, we studied the temperature evolution of the electronic structure of EuFe$_2$As$_2$, an unique pnictide, where antiferromagnetism of Eu layer survives within the superconducting phase due to `FeAs' layers achieved via substitution and/or pressure. High energy and angle resolution helped to reveal pseudogap-quasiparticle features having primarily As 4$p$ character and spin density wave transition induced band folding in the electronic structure. A weakly dispersing feature of dominant As 4$p$ character is discovered around 80 meV that becomes weaker in intensity below 20 K manifesting influence of antiferromagnetic order on conduction electrons. These results provide an evidence of a link between the pseudogap states and magnetism that could be revealed employing high resolutions.