Spin excitations in K${}_2$Fe${}_{4+x}$Se${}_5$: linear response approach

Abstract

Using \emph{ab initio} linear response techniques we calculate spin wave spectra in K${}_2$Fe${}_{4+x}$Se${}_5$, and find it to be in excellent agreement with a recent experiment. The spectrum can be alternatively described rather well by localized spin Hamiltonian restricted to first and second nearest neighbor couplings. We confirm that exchange coupling between nearest neighbor Fe magnetic moments is strongly anisotropic, and show directly that in the ideal system this anisotropy has itinerant nature which can be imitated by introducing higher order terms in effective localized spin Hamiltonian (biquadratic coupling). In the real system, structural relaxation provides an additional source of the exchange anisotropy of approximately the same magnitude. The dependence of spin wave spectra on filling of Fe vacancy sites is also discussed.

References in corpus (12)

• The Puzzle of High Temperature Superconductivity in Layered Iron Pnictides and Chalcogenides
• A Novel Large Moment Antiferromagnetic Order in K0.8Fe1.6Se2 Superconductor
• Microstructure and Fe-vacancy ordering in the KFexSe2 superconducting system
• Neutron Studies of the Iron-based Family of High TC Magnetic Superconductors
• Consistent model of magnetism in ferropnictides
• On the Structure of Vacancy Ordered Superconducting Alkali Metal Iron Selenide
• Spin Waves and magnetic exchange interactions in insulating Rb${}_{0.89}$Fe${}_{1.58}$Se${}_2$
• Block Spin Ground State and 3-Dimensionality of (K,Tl)Fe${}_{1.6}$Se${}_2$
• The exchange coupling and spin waves in metallic magnets: removal of the long-wave approximation
• Spin wave dispersion based on the quasiparticle self-consistent $GW$ method: NiO, MnO and $\alpha$-MnAs
• An unified minimum effective model of magnetism in iron-based superconductors
• Structural, Magnetic and Electronic Properties of the Iron-Chalcogenide A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Cs, Rb, Tl and etc.) Superconductors

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• Intrinsic magnetic properties of {$R$(Fe${}_{1-x}$Co${}_x$)${}_{11}$Ti$Z$} ($R$ = Y and Ce; $Z$ = H, C, and N)
• Giant biquadratic interaction induced magnetic anisotropy in the iron-based superconductor AxFe2-ySe2
• Neutron Scattering Study on Spin Dynamics in Superconducting (Tl,Rb)2Fe4Se5
• Magnetic anisotropic energy gap and low energy spin wave excitation in antiferromagnetic block phase of K2Fe4Se5
• Magnetic interactions and excitations in SrMnSb${}_2$