Electronic Structure of KFe₂Se₂ from First Principles Calculations

الأصل · EN

Electronic structure and magnetic properties for iron-selenide KFe₂Se₂ are studied by first-principles calculations. The ground state is stripe-like antiferromagnetic with calculated 2.26 μB magnetic moment on Fe atoms; and the J₁, J₂ coupling strengths are calculated to be 0.038 eV and 0.029 eV. The states around EF are dominated by the Fe-3d orbitals which hybridize noticeably to the Se-4p orbitals. While the band structure of KFe₂Se₂ is similar to a heavily electron-doped BaFe₂As₂ or FeSe system, the Fermi surface of KFe₂Se₂ is much closer to 11 system since the electron sheets around M is symmetric with respect to x-y exchange. These features, as well as the absence of Fermi surface nesting, suggest that the parental KFe₂Se₂ could be regarded as an electron over-doped 11 system with possible local moment magnetism.