Fermi surfaces and quasi-particle band dispersions of the iron pnictides superconductor KFe2As2 observed by angle-resolved photoemission spectroscopy

TL;DR

This study uses angle-resolved photoemission spectroscopy to analyze the Fermi surfaces and band dispersions in the superconductor KFe2As2, revealing deviations from theoretical predictions and suggesting many-body effects.

Contribution

It provides detailed experimental observations of the electronic structure of KFe2As2, highlighting discrepancies with band-structure calculations and emphasizing the role of many-body interactions.

Findings

Most Fermi surfaces are nearly two-dimensional

One quasi-particle band shows strong kz dispersion

Hole Fermi surfaces are smaller than predicted

Abstract

We have performed an angle-resolved photoemission study of the iron pnictide superconductor KFe2As2 with Tc 4 K. Most of the observed Fermi surfaces show almost two-dimensional shapes, while one of the quasi-particle bands near the Fermi level has a strong dispersion along the kz direction, consistent with the result of a band-structure calculation. However, hole Fermi surfaces \alpha and \zeta are smaller than those predicted by the calculation while other Fermi surfaces are larger. These observations are consistent with the result of a de Haas-van Alphen study and a theoretical prediction on inter-band scattering, possibly indicating many body effects on the electronic structure.