Spin Excitation Anisotropy as a Probe of Orbital Ordering in the Paramagnetic Tetragonal Phase of Superconducting BaFe1.904Ni0.096As2
Spin Excitation Anisotropy as a Probe of Orbital Ordering in the Paramagnetic Tetragonal Phase of Superconducting BaFe1.904Ni0.096As2
复制标题
自旋激发各向异性作为超导 BaFe1.904Ni0.096As2 顺磁四方相轨道有序性的探针
DOI：
10.1103/physrevlett.111.107006
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发表时间：
2013-09-05
影响因子：
8.6
通讯作者：
Dai, Pengcheng
中科院分区：
文献类型：
--
作者：
Luo, Huiqian;Wang, Meng;Dai, Pengcheng
利用极化中子散射研究了电子掺杂超导体BaFe1.904Ni0.096As2(T-c=19.8K)的面内自旋激发，发现在远高于反铁磁有序和四方-正交晶格扭曲温度(T-N近似于T-S=33+/-2K)的四方相中，自旋激发从各向同性转变为各向异性.虽然各向异性自旋激发对AFM有序性和四方晶格畸变不敏感，但超导电性使自旋激发沿[110]和[1(1)Over Bar0]方向进一步各向异性。这些结果表明，自旋激发各向异性是铁化合物四方相中电子各向异性或轨道有序性的探针。
We use polarized neutron scattering to demonstrate that in-plane spin excitations in electron doped superconducting BaFe1.904Ni0.096As2 (T-c = 19.8 K) change from isotropic to anisotropic in the tetragonal phase well above the antiferromagnetic (AFM) ordering and tetragonal-to-orthorhombic lattice distortion temperatures (T-N approximate to T-s = 33 +/- 2 K) without an uniaxial pressure. While the anisotropic spin excitations are not sensitive to the AFM order and tetragonal-to-orthorhombic lattice distortion, superconductivity induces further anisotropy for spin excitations along the [110] and [1 (1) over bar0] directions. These results indicate that the spin excitation anisotropy is a probe of the electronic anisotropy or orbital ordering in the tetragonal phase of iron pnictides.