发表机构
George Mason University; University of Notre Dame（乔治梅森大学; 圣母大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究Co插层和交替磁序对Co$_{1/4}$NbSe$_2$晶格动力学的影响，利用偏振分辨拉曼光谱和密度泛函理论，发现Co插层驱动振动光谱重构，揭示了自旋-声子耦合，证明插层对过渡金属二卤化物振动性质有重大影响。
AI 中文摘要
我们研究了Co插层和交替磁序对层状化合物Co$_{1/4}$NbSe$_2$晶格动力学的影响。通过密度泛函理论支持的偏振分辨拉曼光谱，识别出六个拉曼活性声子。Co插层通过NbSe$_2$声子的区折叠驱动振动光谱的大量重构，产生具有混合区中心和区边界特征的杂化模式。温度相关拉曼测量显示在交替磁转变中无间断，这与准一维Co链中的短程自旋相关性一致。此外，发现A$_{1g}$对称模式中由于面外Se位移存在自旋-声子耦合。我们的工作证明了插层对过渡金属二卤化物振动性质的重大影响以及新发现的交替磁材料中自旋-声子相互作用的存在。
英文摘要
We investigate the influence of Co intercalation and altermagnetic order on the lattice dynamics of the layered compound Co$_{1/4}$NbSe$_2$. Polarization-resolved Raman spectroscopy, supported by density-functional theory, enables identification of six Raman-active phonons. Co intercalation drives a substantial reconstruction of the vibrational spectrum through zone folding of NbSe$_2$ phonons, producing hybridized modes with mixed zone-center and zone-boundary character. Despite this, Co atoms do not participate in any Raman-active modes by symmetry, which is in marked contrast to related $1/3$ compounds where intercalant modes do contribute to the Raman spectrum. Temperature-dependent Raman measurements across the altermagnetic transition show no discontinuities, which is consistent with magnetic fluctuations persisting above the Néel temperature. However, we find evidence for spin-phonon coupling in $A_{1g}$ symmetry modes owing to their out-of-plane Se displacements. Our work demonstrates the substantial impact of intercalation on the vibrational properties of transition metal dichalcogenides and the presence of spin-phonon interactions in a newly discovered altermagnetic material.
CommentsMain text 8 pages. Supplementary text 12 pages
