Structural, electronic properties and Fermi surface of ThCr2Si2-type   charge-balanced KFe2AsSe phase as a parent system for a new group of "mixed"   pnictide-chalcogenide superconductors
  The ThCr2Si2-type arsenide-selenide phase KFe2AsSe is proposed as a parent system for a new "intermediate" group of Fe-based superconducting materials bridging the known families of Fe-pnictides (such as BaFe2As2) and Fe-chalcogenides (such as KxFe2-ySe2) superconductors. The characterization of the proposed charge-balanced phase by means of FLAPW-GGA approach covers the crystal structure, As/Se atomic ordering, stability, electronic bands, Fermi surface, and density of electronic states. 
Igor R. Shein and Alexander L. Ivanovskii
cond-mat.supr-con