在半导体 K0.85 Fe1.54Se2（TN = 280 K）中空间各向异性磁交换相互作用的中子散射测量。
Neutron scattering measurements of spatially anisotropic magnetic exchange interactions in semiconducting K0.85 Fe1.54Se2 (TN = 280 K.
机构信息
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Department of Physics, University of California, Berkeley, California 94720, USA and Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
出版信息
Phys Rev Lett. 2014 May 2;112(17):177002. doi: 10.1103/PhysRevLett.112.177002. Epub 2014 Apr 30.
We use neutron scattering to study the spin excitations associated with the stripe antiferromagnetic 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 inplane 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 inplane 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.
我们使用中子散射来研究与半导体 K(0.85)Fe(1.54)Se(2)（T(N) = 280 K）中的条纹反铁磁序相关的自旋激发。我们表明，在 T = 5 K 时，自旋波谱可以通过具有高度各向异性面内耦合的有效海森堡哈密顿量准确地描述。在高于 T(N) 的高温（T = 300 K）下，观察到具有各向异性相关长度的短程磁关联。我们的结果表明，尽管费米面拓扑结构存在显著差异，但面内各向异性磁耦合是铁基化合物的基本性质；这意味着它们的反铁磁性可能源于局部强关联效应，而不是弱耦合费米面嵌套。
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