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

Abstract:

We have performed an angle-resolved photoemission study of the iron pnictide superconductor KFe₂As₂ with  T_c~  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 k_z direction, consistent with the result of a band-structure calculation. However, hole Fermi surfaces α and ζ 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.