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arXiv · 1405.4737

Neutron Scattering Measurements of Spatially Anisotropic Magnetic Exchange Interactions in Semiconducting K0.85Fe1.54Se2 (TN=280 K)

Jun Zhao·Yao Shen·R. J. Birgeneau·Miao Gao·Zhong-Yi Lu·D. -H. Lee·X. Z. Lu·H. J. Xiang·D. L. Abernathy·Y. Zhao
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Abstract

We use neutron scattering to study the spin excitations associated with the stripe antiferromagnetic (AFM) order in semiconducting K$_{0.85}$Fe$_{1.54}$Se$_2$ ($T_N$=$280$ K). We show that the spin wave spectra can be accurately described by an effective Heisenberg Hamiltonian with highly anisotropic in-plane couplings at $T$= $5$ K. At high temperature ($T$= $300$ K) above $T_N$, short range magnetic correlation with anisotropic correlation lengths are observed. Our results suggest that, despite the dramatic difference in the Fermi surface topology, the in-plane anisotropic magnetic couplings are a fundamental property of the iron based compounds; this implies that their antiferromagnetism may originate from local strong correlation effects rather than weak coupling Fermi surface nesting.

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Jun Zhao, Yao Shen, R. J. Birgeneau, Miao Gao, Zhong-Yi Lu, D. -H. Lee, X. Z. Lu, H. J. Xiang, D. L. Abernathy, Y. Zhao. 2014-05-19. Neutron Scattering Measurements of Spatially Anisotropic Magnetic Exchange Interactions in Semiconducting K0.85Fe1.54Se2 (TN=280 K). https://doi.org/10.1103/physrevlett.112.177002

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