论文标题

Caspar-Klug lattices上偶极子方向的对称破坏

Symmetry breaking of dipole orientations on Caspar-Klug lattices

论文作者

Čopar, Simon, Božič, Anže

论文摘要

各向异性偶极 - 偶极相互作用通常在生物,柔软和复杂物质中起关键作用。为了在系统中诱导非平凡的顺序,必须有其他排斥相互作用或涉及的外部电位部分或完全固定偶极子的位置。这些位置通常可以表示为偶极相互作用的基础晶格,引起颗粒的定向排序。在欧几里得平面的晶格上,已经发现偶极子根据晶格类型假设不同的基态构型,并且在许多情况下观察到了宏观的全局顺序。最近,基于汤姆森问题的解决方案,类似的偶极子的大型摩值构型是位于球形晶格上的偶极子的唯一基态。同时,即使汤姆森晶格的位置顺序表现出高度的对称性,也未观察到对称配置。在这里,我们表明,基于Caspar-Klug构造的球形晶格选择不同,导致具有不同程度的对称性的偶极子的基态,包括基础晶格的二十面体对称性。我们分析了高度对称亚稳态状态的稳定性,它们的对称性分解为二十面体对称组的亚对称性,并呈现相对于晶格参数的对称性相图。观察到的位置顺序与偶极子诱导的对称性破坏的暗示是通过微调球形组件及其设计的方式进行的。

Anisotropic dipole-dipole interaction often plays a key role in biological, soft, and complex matter. For it to induce non-trivial order in the system, there must be additional repulsive interactions or external potentials involved that partially or completely fix the positions of the dipoles. These positions can often be represented as an underlying lattice on which dipole interaction induces orientational ordering of the particles. On lattices in the Euclidean plane, dipoles have been found to assume different ground state configurations depending on the lattice type, with a global ordering in the form of a macrovortex being observed in many cases. A similar macrovortex configuration of dipoles has recently been shown to be the sole ground state for dipoles positioned on spherical lattices based on solutions of the Thomson problem. At the same time, no symmetric configurations have been observed, even though the positional order of Thomson lattices exhibits a high degree of symmetry. Here, we show that a different choice of spherical lattices based on Caspar-Klug construction leads to ground states of dipoles with various degrees of symmetry, including the icosahedral symmetry of the underlying lattice. We analyze the stability of the highly symmetric metastable states, their symmetry breaking into subsymmetries of the icosahedral symmetry group, and present a phase diagram of symmetries with respect to lattice parameters. The observed relationship between positional order and dipole-induced symmetry breaking hints at ways of fine-tuning the structure of spherical assemblies and their design.

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