标题： 奇异晶体的异常晶粒动力学和晶粒运动 显示英文标题

标题： Anomalous grain dynamics and grain locomotion of odd crystals

摘要： 调控奇异弹性响应的晶体或多晶系统被认为表现出复杂的动力学行为，涉及拓扑缺陷的自推进动力学以及手性晶体的自发自旋。 揭示和控制这些基本机制需要跨多个尺度的研究。 我们开发了一种方法，该方法以相场晶体模型的形式，在微观和介观尺度之间架起桥梁，并结合横向相互作用。 这种连续密度场理论具有二维宇称对称性破缺和奇异弹性，并产生各种有趣的现象，这些现象与最近关于活性和生命手性晶体的实验和基于粒子的模拟结果非常一致，包括自旋转晶体、位错的自推进和增殖，以及多晶中的碎裂。 我们发现了一种由自生表面奇异应力引起的独特类型的表面尖点不稳定性，导致单晶粒的自分裂。 这一机制对于奇异晶体的各种异常晶粒动力学至关重要，特别是对于自旋转奇异晶粒从正常到反向奥斯特瓦尔德熟化的预测，以及在动态多晶态中随着横向相互作用强度增加，从晶粒粗化到晶粒自碎裂的转变。 我们还证明，单个晶粒的动力学可以通过调节粒子间的横向相互作用来操控。 这允许引导晶粒运动的期望路径，并控制晶粒自旋、自转和自平移之间的转换。 我们的研究结果为活性奇异弹性材料的结构和动力学特性的设计和控制提供了见解。 显示英文摘要

摘要： Crystalline or polycrystalline systems governed by odd elastic responses are known to exhibit complex dynamical behaviors involving self-propelled dynamics of topological defects with spontaneous self-rotation of chiral crystallites. Unveiling and controlling the underlying mechanisms require studies across multiple scales. We develop such a type of approach that bridges between microscopic and mesoscopic scales, in the form of a phase field crystal model incorporating transverse interactions. This continuum density field theory features two-dimensional parity symmetry breaking and odd elasticity, and generates a variety of interesting phenomena that agree well with recent experiments and particle-based simulations of active and living chiral crystals, including self-rotating crystallites, dislocation self-propulsion and proliferation, and fragmentation in polycrystals. We identify a distinct type of surface cusp instability induced by self-generated surface odd stress that results in self-fission of single-crystalline grains. This mechanism is pivotal for the occurrence of various anomalous grain dynamics for odd crystals, particularly the predictions of a transition from normal to reverse Ostwald ripening for self-rotating odd grains, and a transition from grain coarsening to grain self-fragmentation in the dynamical polycrystalline state with an increase of transverse interaction strength. We also demonstrate that the single-grain dynamics can be maneuvered through the variation of interparticle transverse interactions. This allows to steer the desired pathway of grain locomotion and to control the transition between grain self-rotation, self-rolling, and self-translation. Our results provide insights for the design and control of structural and dynamical properties of active odd elastic materials.