State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Research Center for Neutron Science and Technology, Comprehensive Research Organization for Science and Society, Tokai, Ibaraki 319-1106, Japan.
Nat Commun. 2016 Jul 19;7:12182. doi: 10.1038/ncomms12182.
Elucidating the nature of the magnetism of a high-temperature superconductor is crucial for establishing its pairing mechanism. The parent compounds of the cuprate and iron-pnictide superconductors exhibit Néel and stripe magnetic order, respectively. However, FeSe, the structurally simplest iron-based superconductor, shows nematic order (Ts=90 K), but not magnetic order in the parent phase, and its magnetic ground state is intensely debated. Here we report inelastic neutron-scattering experiments that reveal both stripe and Néel spin fluctuations over a wide energy range at 110 K. On entering the nematic phase, a substantial amount of spectral weight is transferred from the Néel to the stripe spin fluctuations. Moreover, the total fluctuating magnetic moment of FeSe is ∼60% larger than that in the iron pnictide BaFe2As2. Our results suggest that FeSe is a novel S=1 nematic quantum-disordered paramagnet interpolating between the Néel and stripe magnetic instabilities.
阐明高温超导体的磁性本质对于确定其配对机制至关重要。铜酸盐和铁磷族超导材料的母体化合物分别表现出奈尔和条纹磁有序。然而，结构最简单的铁基超导体 FeSe 在母体相中表现出向列序（Ts=90K），而不是磁有序，其磁基态存在激烈争议。在这里，我们报告了非弹性中子散射实验结果，这些结果表明在 110K 时，在很宽的能量范围内存在条纹和奈尔自旋涨落。进入向列相时，大量的光谱权重从奈尔向条纹自旋涨落转移。此外，FeSe 的总涨落磁矩比铁磷族化合物 BaFe2As2 中的大约 60%。我们的结果表明，FeSe 是一种新颖的 S=1 向列量子无序顺磁体，介于奈尔和条纹磁不稳定性之间。
Zotero 插件
