发表机构
Sandia National Laboratories; Carnegie Mellon University（桑迪亚国家实验室; 卡内基梅隆大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分子动力学模拟发现，沿螺旋轴剪切向列扭曲-弯曲相会产生merons缺陷，这些缺陷作为拓扑机器重排棒取向，为控制merons和设计功能材料提供新机制。
AI 中文摘要
弯曲核液晶是软物质系统的一个典型例子，其行为由一种无法普遍实现的局部有序偏好所控制。这种由棒的弯曲形状引起的几何挫败，已被证明能够稳定多种平衡相，例如螺旋有序的向列扭曲-弯曲相（$N_{\rm TB}$）。与传统向列相不同，扭曲-弯曲态具有一维平移有序性，这种有序性源于弯曲取向沿螺旋轴的周期性旋转。在这里，我们使用分子动力学模拟来研究沿平行于和垂直于螺旋轴方向剪切$N_{\rm TB}$相的效果。在垂直于螺旋轴剪切的情况下，向列扭曲-弯曲相是稳定的，并且流动时不会发生无序化。相反，沿螺旋轴剪切会破坏有序性，并导致分数电荷的Skyrmion缺陷（即merons）的出现。这些缺陷充当拓扑机器，局部旋转棒，使其进入$N_{\rm TB}$相的重排且稳定的取向。这些发现揭示了一种产生和控制merons的新机制，并强调了弯曲核液晶在设计具有特定光学和计算性能的功能材料中的潜在应用。
英文摘要
Bent-core liquid crystals are a canonical example of a soft matter system whose behavior is controlled by a local preference for order that cannot be universally achieved. This geometric frustration, arising from the rod's curved shape, has been shown to stabilize a variety of equilibrium phases, such as the helically ordered nematic twist-bend phase ($N_{\rm TB}$). Unlike a traditional nematic, the twist-bend state has 1D translational order arising from a periodic rotation of bend orientation along the helical axis. Here, we use molecular dynamics simulations to study the effect of shearing the $N_{\rm TB}$ phase along directions parallel and perpendicular to the helical axis. In the case of shear perpendicular to the helical axis, the nematic twist-bend phase is stable and flows without disordering. Conversely, shear along the helical axis disrupts order and leads to the emergence of fractionally charged Skyrmion defects, i.e. merons. These defects act as topological machines, locally rotating rods into a re-ordered and stable orientation of the $N_{\rm TB}$ phase. These findings reveal a new mechanism to create and control merons and highlight the potential application of bent-core liquid crystals in designing functional material with specific optical and computational properties.
Comments15 pages, 10 figures
