Condensation of collective polar vortex modes
Condensation of collective polar vortex modes
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DOI：
10.1103/physrevb.103.l220303
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发表时间：
2021-06
影响因子：
3.7
通讯作者：
Tiannan Yang;C. Dai;Qian Li;H. Wen;Long-qing Chen
中科院分区：
文献类型：
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作者：
Tiannan Yang;C. Dai;Qian Li;H. Wen;Long-qing Chen
扩展对象的动力学，例如畴壁、畴泡、涡旋结构等，可以通过与其有效质量和弹簧常数相关的运动方程来描述。在这里，我们解析推导出运动方程的极化动力学和弹性动力学的铁电极涡的结构响应，并从理论上提取其有效质量，弹簧常数，和模式频率。我们展示了两个亚太赫兹声子模式，并预测了它们的频率，这与我们最近的实验测量和相场模拟一致。我们表明，弹性调制的能量函数和弹簧常数导致凝聚的集体模式后，从对称到不对称的涡旋在临界应变的二阶结构转变，类似于铁电体的软声子模式在铁电过渡。目前的工作提供了一个理论框架，预测和操纵极性纳米结构的超快集体动力学。
The dynamics of extended objects such as domain walls, domain bubbles, vortex structures, etc., can be described by their equations of motion associated with their effective mass and spring constant. Here we analytically derive the equations of motion for the polarization dynamics and elastodynamics for the structural responses of ferroelectric polar vortices, and theoretically extract their effective mass, spring constant, and mode frequencies. We demonstrate two subterahertz phonon modes and predicted their frequencies, both consistent with our recent experimental measurements and phase-field simulations. We show that elastic modulation of the energy function and spring constants leads to a condensation of a collective mode upon a second-order structural transition from symmetric to asymmetric vortices at a critical strain, analogous to the ferroelectric soft phonon mode at a ferroelectric transition. The present work offers a theoretical framework for predicting and manipulating the ultrafast collective dynamics of polar nanostructures.