AI 中文总结
研究对称控制磁性材料中自旋 - 声子耦合机制，通过温度和极化分辨拉曼光谱等方法，在g型反磁体CoNb4Se8及Co缺陷化合物中展开研究，确定了自旋 - 声子耦合新机制，为量子材料中自旋 - 晶格功能研究提供框架。
AI 中文摘要
对称控制的磁性材料已成为无净磁化或杂散磁场的自旋电子功能的有前景平台，促使人们探索晶格动力学如何与对称衍生的自旋极化电子态耦合。理解这些系统中的自旋 - 声子耦合对于揭示自旋 - 晶格相互作用的微观起源并实现其在量子材料中的控制至关重要。然而，由于自旋极化源于晶体对称性而非传统磁序，该机制仍知之甚少。在此，我们使用温度和极化分辨拉曼光谱研究了g型反磁体CoNb4Se8中的这一问题，并对缺乏明确长程磁序的结构类似的Co缺陷化合物进行了测量。我们观察到CoNb4Se8在磁转变过程中存在明显的对称选择性声子重整化，而相关声子异常在Co缺陷系统中持续存在，这表明晶格响应不能仅用与相干磁序相关的传统交换收缩来解释。第一性原理计算表明，自旋 - 轨道耦合在晶格振动和对称控制的电子态之间建立了对称依赖的相互作用通道。我们的结果确定了对称控制的磁性材料中自旋 - 声子耦合的另一种机制，并表明即使没有强磁序，声子也能提供对称驱动自旋极化的灵敏探针。更广泛地说，这项工作为理解和设计对称驱动量子材料中的自旋 - 晶格功能提供了框架，为将晶格动力学与自旋极化电子态耦合提供了设计原则。
英文摘要
Symmetry-governed magnetic materials have emerged as a promising platform for spintronic functionalities without net magnetization or stray magnetic fields, motivating the exploration of how lattice dynamics couple to symmetry-derived spin-polarized electronic states. Understanding spin-phonon coupling in these systems is therefore essential for uncovering the microscopic origin of spin-lattice interactions and for enabling their control in quantum materials. However, this mechanism remains poorly understood because spin polarization originates from crystal symmetry rather than conventional magnetic order. Here, we address this issue in the g-type altermagnet CoNb4Se8 using temperature- and polarization-resolved Raman spectroscopy, complemented by measurements on a structurally analogous Co-deficient compound lacking well-defined long-range magnetic order. We observe pronounced symmetry-selective phonon renormalization across the magnetic transition in CoNb4Se8, while related phonon anomalies persist in the Co-deficient system, demonstrating that the lattice response cannot be explained solely by conventional exchange-striction associated with coherent magnetic ordering. First-principles calculations reveal that spin-orbit coupling establishes a symmetry-dependent interaction channel between lattice vibrations and symmetry-governed electronic states. Our results identify an alternative mechanism for spin-phonon coupling in symmetry-governed magnetic materials and demonstrate that phonons provide a sensitive probe of symmetry-driven spin polarization even without robust magnetic order. More broadly, this work provides a framework for understanding and engineering spin-lattice functionality in symmetry-driven quantum materials, offering design principles for coupling lattice dynamics to spin-polarized electronic states.
