非共线磁体中非相对论隐藏自旋极化的对称性分类
Symmetry Classification of Non-Relativistic Hidden Spin Polarization in Noncollinear Magnets
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中文总结 AI 辅助
本文基于自旋群理论建立非共线磁体隐藏自旋极化的对称性框架，将其分为三类并确定候选材料，为理解该现象及相关功能应用提供通用方法。
中文摘要 AI 辅助
隐藏自旋极化（HSP）是指自旋极化态局部存在，而总自旋极化在动量空间中被隐藏的现象，该现象已在非磁和共线磁体系中得到广泛研究，但在非共线磁体中仍未被充分探索。本文基于自旋群理论，建立了非共线磁性材料中HSP的统一对称性框架。研究表明，自旋对称性系统地约束了非相对论自旋极化，为每个局域区域产生四种不同的分裂自旋纹理（SST）类型，分别记为SST-1、SST-2、SST-3和SST-4。基于这些分裂形式，结合相关局域自旋纹理的维度以及不同局域区域之间的对称关系，进一步将HSP分为三类：HSP-1、HSP-2和HSP-3。本文采用紧束缚模型及代表性材料实例（包括SrFe₂Se₂O、USb、Sr₂Mn₃Sb₂O₂、PrFeAsO和GdMn₂Si₂）对这些类别进行了说明。对MAGNDATA数据库的调研进一步确定了分别包含HSP-1、HSP-2和HSP-3的候选非共线磁性材料有133种、7种和139种。此外，对称性分析和第一性原理计算表明，这些材料中的许多可表现出非零的自旋相关响应张量。这些结果为理解非共线磁体中的HSP建立了通用框架，并凸显了其在自旋相关功能方面的潜力。
英文摘要
Hidden spin polarization (HSP), in which spin-polarized states exist locally while the total spin polarization are hidden in momentum space, has been extensively studied in nonmagnetic and collinear magnetic systems, but remains largely unexplored in noncollinear magnets. Here we establish a unified symmetry framework for HSP in noncollinear magnetic materials based on spin-group theory. We show that spin symmetries systematically constrain nonrelativistic spin polarization, giving rise to four distinct split spin-texture (SST) types for each local sector, denoted as SST-1, SST-2, SST-3, and SST-4. Based on these splitting forms, together with the dimensionality of the associated local spin textures and the symmetry relations between different local sectors, we further classify HSP into three categories: HSP-1, HSP-2, and HSP-3. We illustrate these categories using tight-binding models and representative material examples, including SrFe$_2$Se$_2$O, USb, Sr$_2$Mn$_3$Sb$_2$O$_2$, PrFeAsO, and GdMn$_2$Si$_2$. A survey of the MAGNDATA database further identifies 133, 7, and 139 candidate noncollinear magnetic materials hosting HSP-1, HSP-2, and HSP-3, respectively. In addition, our symmetry analysis and first-principles calculation show that many of these materials can exhibit nonzero spin-related response tensors. These results establish a general framework for understanding HSP in noncollinear magnets and highlight their potential for spin-dependent functionalities.
