K$_5$Fe$_4$Ag$_6$Te$_{10}$中畴的孪生与自旋各向异性
Twinning of domains and spin anisotropy in K$_5$Fe$_4$Ag$_6$Te$_{10}$
浏览论文内容
中文总结 AI 辅助
本研究通过中子衍射完整映射KFAT的倒空间，阐明其超结构畴与磁畴的孪生关系，并利用极化中子散射揭示持续至高温的自旋各向异性，为寻找压磁效应提供指标。
中文摘要 AI 辅助
铁基超导体源自具有向列相和条纹磁序的金属母体化合物，这些磁序导致两类磁畴。最近发现，铁基半导体K$_5$Fe$_4$Ag$_6$Te$_{10}$（KFAT）表现出类似的向列相和条纹磁序，因此是局域电子极限下铁基超导体的类似物。在本工作中，通过使用飞行时间单晶中子衍射对倒空间进行完整映射，阐明了KFAT的超结构和磁畴。在KFAT中，Fe和Ag原子有序排列形成包含$2\times2$ Fe块的$\sqrt{5}\times\sqrt{5}$超结构，这导致两个具有相同主布拉格峰但不同超结构峰的超结构畴。在$T_{\rm N}\approx35$~K以下，磁序和向列序打破了四方$\sqrt{5}\times\sqrt{5}$超结构的面内旋转对称性，并进一步产生两个磁畴。这四个等布居的畴解释了我们在飞行时间弹性中子散射测量中观察到的复杂散射图案。利用极化中子散射，我们证明了显著的自旋各向异性，其易平面由$c$轴和块内反铁磁Fe-Fe键方向张成。这种在${\bf q}\neq0$处的各向异性在远高于$T_{\rm N}$时持续存在，解释了在单轴应变KFAT中观察到的面内${\bf q}=0$磁各向异性，并为在其他材料中发现类似压磁效应提供了指标。
英文摘要
The Fe-based superconductors are derived from metallic parent compounds with nematic and stripe magnetic orders, which lead to two types of magnetic domains. Recently it was found that K$_5$Fe$_4$Ag$_6$Te$_{10}$ (KFAT), an Fe-based semiconductor, exhibits similar nematic and stripe magnetic orders, and is thus an analogue to the Fe-based superconductors in the limit of localized electrons. In this work, the superstructure and magnetic domains of KFAT are elucidated by fully mapping the reciprocal space using time-of-flight single crystal neutron diffraction. In KFAT, Fe and Ag atoms order to form a $\sqrt{5}\times\sqrt{5}$ superstructure containing $2\times2$ Fe blocks, which leads to two superstructure domains with identical main Bragg peaks but distinct superstructure peaks. Below $T_{\rm N}\approx35$~K, magnetic and nematic orders break in-plane rotational symmetry of the tetragonal $\sqrt{5}\times\sqrt{5}$ superstructure, and further give rise to two magnetic domains. These four equally populated domains account for the complex scattering pattern observed in our time-of-flight elastic neutron scattering measurements. Using polarized neutron scattering, we demonstrate a prominent spin anisotropy with an easy-plane spanned by the $c$-axis and the intra-block antiferromagnetic Fe-Fe bond direction. Such an anisotropy at ${\bf q}\neq0$ persists well above $T_{\rm N}$, accounts for the in-plane ${\bf q}=0$ magnetic anisotropy observed in uniaxial-strained KFAT, and offers an indicator for discovering similar piezomagnetic effects in other materials.
发表机构
- Center for Correlated Matter and School of Physics, Zhejiang University（浙江大学相关物质中心与物理学院）
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University（北京师范大学先进量子研究中心与物理系）
- Materials Science Division, Lawrence Berkeley National Lab（劳伦斯伯克利国家实验室材料科学部）
- State Key Laboratory of Functional Crystals and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences（中国科学院上海陶瓷研究所功能晶体及器件国家重点实验室）
- Laboratory for Neutron Scattering, School of Physics, Renmin University of China（中国人民大学物理学院中子散射实验室）
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China（中国人民大学量子态构建与操控教育部重点实验室）
- Department of Physics, University of California, Berkeley（加州大学伯克利分校物理系）
- Japan Synchrotron Radiation Research Institute, SPring-8（日本同步辐射研究机构SPring-8）
- Neutron Scattering Division, Oak Ridge National Laboratory（橡树岭国家实验室中子散射部）
机构由 AI 辅助整理，请以论文原文为准。
