发表机构
Institute of Theoretical Physics, Chinese Academy of Sciences; School of Physical Sciences, University of Chinese Academy of Sciences; School of Physics and Information Technology, Shaanxi Normal University; Center for Theoretical Interdisciplinary Sciences, Wenzhou Institute, University of Chinese Academy of Sciences（中国科学院理论物理研究所; 中国科学院大学物理科学学院; 陕西师范大学物理学与信息技术学院; 中国科学院大学温州研究院交叉科学中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究揭示二维晶体中声子涡旋的产生源于晶格对称性，重杂质与剪切变形可分别促进或抑制涡旋，提出的对称与能量框架为调控晶体振动模式提供了有效策略。
AI 中文摘要
声子涡旋是二维材料振动模式中出现的涡旋状位移场。本研究证明，这些涡旋作为简并平面声子模式的对称适配线性组合出现，叠加系数由晶格点群唯一确定。该对称原理表明，涡旋是完美晶体中的本征驻波解，无需杂质或无序。重质量杂质通过更强的共振诱导频率软化，使涡旋模式优于平面模式；而剪切变形通过破坏旋转对称性抑制涡旋模式。这两种效应的竞争产生了可精确预测的应变阈值。基于对称性和能量最小化的所提框架，为理解由其他类型杂质或缺陷诱导的振动拓扑缺陷提供了有用基础。本研究进一步表明，缺陷与剪切工程是控制晶体振动模式及相关热学、力学性质的有效调控策略。
英文摘要
Phonon vortices are vortex-like displacement fields that appear in the vibrational modes of two- dimensional materials. Here, we demonstrate that these vortices arise as symmetry-adapted linear combinations of degenerate planar phonon modes, with the superposition coefficients uniquely de- termined by the lattice point group. This symmetry principle establishes that vortices are intrinsic standing-wave solutions in perfect crystals, requiring neither impurities nor disorder. A heavy mass impurity favors vortex modes over planar modes through stronger resonance-induced frequency soft- ening, whereas shear deformation suppresses vortex modes by breaking rotational symmetry. The competition between these two effects gives rise to a precisely predictable strain threshold. The proposed framework, grounded in symmetry and energy-minimization, provides a useful basis for understanding vibrational topological defects induced by other types of impurities or defects. This study further suggests that defect and shear engineering constitutes an effective tuning strategy for controlling vibrational modes and the associated thermal and mechanical properties of crystals.
Comments13 pages
