Non-trivial topological structures, such as vortex-antivortex (V-AV) pairs, have garnered significant attention in the field of condensed matter physics. However, the detailed topological phase transition dynamics of V-AV pairs, encompassing behaviors like self-annihilation, motion, and dissociation, have remained elusive in real space. Here, polar V-AV pairs are employed as a model system, and their transition pathways are tracked with atomic-scale resolution, facilitated by in situ (scanning) transmission electron microscopy and phase field simulations. This investigation reveals that polar vortices and antivortices can stably coexist as bound pairs at room temperature, and their polarization decreases with heating. No dissociation behavior is observed between the V-AV phase at room temperature and the paraelectric phase at high temperature. However, the application of electric fields can promote the approach of vortex and antivortex cores, ultimately leading to their annihilation near the interface. Revealing the transition process mediated by polar V-AV pairs at the atomic scale, particularly the role of polar antivortex, provides new insights into understanding the topological phases of matter and their topological phase transitions. Moreover, the detailed exploration of the dynamics of polar V-AV pairs under thermal and electrical fields lays a solid foundation for their potential applications in electronic devices.

中文翻译：

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极涡-反涡对的原子尺度跟踪拓扑相变动力学


涡旋-反涡旋（V-AV）对等非平凡的拓扑结构在凝聚态物理领域引起了极大的关注。然而，V-AV 对的详细拓扑相变动力学，包括自毁、运动和解离等行为，在现实空间中仍然难以捉摸。在这里，采用极性 V-AV 对作为模型系统，并通过原位（扫描）透射电子显微镜和相场模拟以原子级分辨率跟踪它们的转变路径。这项研究表明，极涡和反涡在室温下可以作为束缚对稳定共存，并且它们的极化随着加热而降低。室温下的 V-AV 相和高温下的顺电相之间没有观察到解离行为。然而，电场的应用可以促进涡核和反涡核的接近，最终导致它们在界面附近湮灭。在原子尺度上揭示极性V-AV对介导的转变过程，特别是极性反涡的作用，为理解物质的拓扑相及其拓扑相变提供了新的见解。此外，对极性V-AV对在热场和电场下的动力学的详细探索为其在电子设备中的潜在应用奠定了坚实的基础。