发表机构
Shiv Nadar Institution of Eminence (SNIoE)（Shiv Nadar卓越机构）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究涡旋节环半金属中赝自旋纹理对等离激元模式的影响，通过随机相位近似分析密度响应等，发现涡旋纹理引入环向角依赖性，修正电荷响应。
AI 中文摘要
我们研究了三维涡旋节环半金属（VNRs）中的集体电荷激发，其赝自旋纹理围绕节环缠绕，与传统的$\mathcal{PT}$对称节环半金属（PTNR）在性质上有所不同。虽然PTNR中的等离激元模式已在姊妹篇arXiv:2609.35373中研究过，这里我们专注于VNR的赝自旋纹理如何改变响应。在低能双带描述和随机相位近似下，我们分析了低掺杂下的密度响应、态密度、Drude权重、介电函数和等离激元模式。我们考虑了无倾斜系统以及面内和轴向能带倾斜。尽管VNR和PTNR具有不同的哈密顿量、赝自旋纹理和Berry曲率分布，它们的线性化能量色散相同。然而，涡旋纹理在能带重叠因子和量子度量中引入了环向角依赖性，从而修正了电荷响应。我们研究了这些效应如何进入不同波矢取向的介电屏蔽和集体模式中。我们的结果阐明了赝自旋纹理（超越能带色散本身）如何影响三维节环半金属中的集体电荷动力学。
英文摘要
We investigate collective charge excitations in three-dimensional semimetals with dipole-like Berry-curvature (BC) profiles, focusing on vortex nodal-ring semimetals (VNRs) and Hopf semimetals (HSMs). The VNR hosts a continuous ring of dipole-like BC sources generated by its winding pseudospin texture, whereas the HSM hosts an ideal BC dipole. This allows us to examine how distinct realisations of dipole-like BC structure affect collective charge dynamics. While plasmon modes in $\mathcal{PT}$-symmetric nodal-ring semimetals (PTNRs) and their gapped cousins were studied in a companion work, arXiv:2609.35373, here we analyse the density response, Drude weights, dielectric function, and plasmon modes of VNRs and HSMs at low doping within the random-phase approximation. For VNRs, we consider untilted, in-plane tilted, and axially tilted systems. Although VNR and PTNR have identical energy dispersions, their distinct eigenstates introduce a toroidal-angle dependence in the band-overlap factor, yielding additional interband contributions for in-plane wavevectors and weak corrections to the screened plasmon frequencies. The toroidal Fermi surface also produces intrinsically anisotropic bare plasmons. In contrast, HSMs have isotropic bare plasmons, with anisotropy arising only through their interband response. Our results show that collective charge dynamics can distinguish different realisations of dipole-like BC structure and reveal pseudospin information beyond the single-particle dispersion.
Commentscompanion paper of arXiv:2609.35373; substantially revised and updated; includes results for Hopf semimetals as well
