High-resolution angle-resolved photoemission spectroscopy study of the electronic structure of EuFe2As2

TL;DR

This study uses high-resolution ARPES to investigate the electronic structure of EuFe2As2, revealing temperature-dependent band evolution, small Fermi pockets, and weak Eu-FeAs coupling, aligning with theoretical calculations.

Contribution

It provides detailed ARPES measurements of EuFe2As2's electronic structure, highlighting complex band behavior and Fermi surface features not explained by simple models.

Findings

Band splitting, folding, and hybridization evolve with temperature.

Tiny electron and hole pockets are observed near (pi,pi).

No significant change across Eu2+ antiferromagnetic transition.

Abstract

We report the high-resolution angle-resolved photoemission spectroscopy studies of electronic structure of EuFe2As2. The paramagnetic state data are found to be consistent with density-functional calculations. In the antiferromagnetic ordering state of Fe, our results show that the band splitting, folding, and hybridization evolve with temperature, which cannot be explained by a simple folding picture. Detailed measurements reveal that a tiny electron Fermi pocket and a tiny hole pocket are formed near (pi,pi) in the (0,0)-(pi,pi) direction, which qualitatively agree with the results of quantum oscillations, considering kz variation of Fermi surface. Furthermore, no noticeable change within the energy resolution is observed across the antiferromagnetic transition of Eu2+ ordering, suggesting weak coupling between Eu sublattice and FeAs sublattice.