Orbital selectivity in the normal state of KFe₂Se₂ superconductor

¹ Institute of Physics, Federal University of Mato Grosso - Cuiabá, MT 78060-900, Brazil
² Leibniz Institute for Solid State and Materials Research Dresden - Helmholtzstr. 20, D-01069 Dresden, Germany
³ School of Chemistry, Cardiff University- Cardiff, CF10 3AT, UK

^(a) lcraco@fisica.ufmt.br (corresponding author)
^(b) leonis@cardiff.ac.uk

Received: 3 June 2021
Accepted: 2 December 2021

Abstract

Using density functional dynamical mean-field theory, we show how correlation effects lead to pseudogap and Kondo-quasiparticle features in the electronic structure of pure and doped KFe₂Se₂ superconductor. Therein, correlation- and doping-induced orbital differentiation are linked to the emergence of an incoherent-coherent crossover in the normal state of KFe₂Se₂ superconductor. This crossover explains the puzzling temperature- and doping-dependent evolution of resistivity and Hall coefficient, seen in experiments of alkali-metal intercalated iron-selenide superconductors. Our microscopic description emphasises the role of incoherent and coherent electronic excitations towards unconventional transport responses of strange, bad metals.