Magnetic anisotropic energy gap and low energy spin wave excitation in antiferromagnetic block phase of K2Fe4Se5

Abstract

Neutron scattering experiments were performed to investigate magnetic order and magnetic excitations in ternary iron chalcogenide K2Fe4Se5. The formation of a superlattice structure below 580 K together with the decoupling between the Fe-vacancy order-disorder transition and the antiferromagnetic order transition appears to be a common feature in the A2Fe4Se5 family. The study of spin dynamics of K2Fe4Se5 reveals two distinct energy gaps at the magnetic Brillouin zone center, which indicates the presence of magnetic anisotropy and the decrease of local symmetry due to electronic and orbital anisotropy. The low-energy spin wave excitations of K2Fe4Se5 can be properly described by linear spin wave theory within a Heisenberg model. Compared to iron pnictides, K2Fe4Se5 exhibits a more two-dimensional magnetism as characterized by large differences not only between out-of-plane and in-plane spin wave velocities, but also between out-of-plane and in-plane exchange interactions.

5 pages, 4 figures, Accepted for publication, Physical Review B: Rapid Communications

References in corpus (10)

• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• Superconductivity at 32 K in single crystal Rb${}_{0.78}$Fe${}_2$Se${}_{1.78}$}
• Neutron Studies of the Iron-based Family of High TC Magnetic Superconductors
• Spin waves in the $(\pi ,0)$ magnetically ordered iron chalcogenide Fe${}_{1.05}$Te
• Anisotropic three-dimensional magnetism in CaFe2As2
• Overview on the physics and materials of the new superconductor KxFe2-ySe2
• Spin-wave excitations and superconducting resonant mode in Cs(x)Fe(2-y)Se2
• Similar zone-center gaps in the low-energy spin-wave spectra of NaFeAs and BaFe2As2
• Spin excitations in K${}_2$Fe${}_{4+x}$Se${}_5$: linear response approach
• Neutron Scattering Study on Spin Dynamics in Superconducting (Tl,Rb)2Fe4Se5

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• Structure, magnetic order and excitations in the 245 family of Fe-based superconductors
• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• Incommensurate antiferromagnetic order in the manifoldly-frustrated SrTb${}_2$O${}_4$ with transition temperature up to 4.28 K
• Magnetic Fluctuations and the Spin-Orbit Interaction in Mott Insulating CoO
• Ground and Applied-Field-Driven Magnetic States of Antiferromagnets