Structural, electronic properties and Fermi surface of ThCr2Si2-type tetragonal KFe2S2, KFe2Se2, and KFe2Te2 phases as parent systems of new ternary iron-chalcogenide superconductors

TL;DR

This study uses first-principles calculations to compare structural and electronic properties of KFe2Ch2 phases, revealing potential for KFe2Te2 as a parent compound in new iron-chalcogenide superconductors.

Contribution

It provides a comparative analysis of KFe2Ch2 phases and suggests KFe2Te2 as a promising candidate for superconductivity research.

Findings

No critical electronic changes with anion substitution (S, Se, Te)

KFe2Te2 shows potential as a parent phase for new superconductors

Electronic structures are consistent across different Ch elements

Abstract

First principles FLAPW-GGA method was used for the comparative study of the structural and electronic properties of three related tetragonal ThCr2Si2-type phases KFe2Ch2, where Ch are S, Se, and Te. The main trends in electronic bands, densities of states and Fermi surfaces for AFe2Ch2 are analyzed in relation to their structural parameters. We found that at the anion replacements (S<->Se<->Te) any critical changes in electronic structure of KFe2Ch2 phases are absent. On the other hand, our analysis of structural and electronic parameters for hypothetical KFe2Te2 allows to assume that this system may be proposed as perspective parent phase for search of new iron-chalcogenide superconducting materials.