A Three-Dimensional Tight-Binding Model and Magnetic Instability of KFe2e2

Abstract

For a newly discovered iron-based high T_c superconducting parent material KFe2Se2, we present an effective three-dimensional five-orbital tight-binding model by fitting the band structures. The three t2g-symmetry orbitals of the five Fe 3d orbitals mainly contribute to the electron-like Fermi surface, in agreement with recent angle-resolved photoemission spectroscopy experiments. To understand the groundstate magnetic structure, the two- and three-dimensional dynamical spin susceptibilities within the random phase approximation are investigated. It obviously shows a sharp peak at wave vector $\mathbf{Q}$ $\sim$ ($\pi$, $\pi$), indicating the magnetic instability of {\it N$\acute{e}$el}-type antiferromagnetic rather than ($\pi$/2, $\pi$/2)-type antiferromagnetic ordering. While along $\text{c}$ axis, it exhibits a ferromagnetic coupling between the nearest neighboring FeSe layers. The difference between the present results and the experimental observation in KxFe2-ySe2 is attributed to the presence of Fe vacancy in the latter.

14 pages, 8 figures

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Cited by in corpus (8)

• The Unexpected Properties of Alkali Metal Iron Selenide Superconductors
• Role of Hydrogen in the Electronic Properties of CaFeAsH-based Superconductors
• Intrinsic high-temperature superconductivity in ternary iron selenides
• Coexistence of localized and itinerant magnetism in intercalated iron-selenide (Li,Fe)OHFeSe
• Band-filling and correlation controlling electronic properties and magnetism in K${}_x$Fe${}_{2-y}$Se${}_2$: A slave boson study
• Impurity-induced sub-gap bound gap states in alkali doped iron chalcogenide superconductors
• Low-energy bound states at interfaces between superconducting and block antiferromagnet regions in KxFe{2-y}Se2
• Magnetization distribution and orbital moment in the non-Superconducting Chalcogenide Compound K0.8Fe1.6Se2