论文标题
在列液晶中订购倾斜和均匀状态的动力学
Ordering Kinetics of Canted and Uniform States in Nematic Liquid Crystals
论文作者
论文摘要
我们通过对nematic $（t> t_c）$进行深度淬火，对nematic $（t_c）$（t <t_c）$ epase $（t <t_c）$进行了三量液晶（NLC）$（d = 3）$的订购动力学的全面研究。用反转对称性代表的$ o（3）$旋转代表的线虫之间的分子间电势可以通过{\ it概括的lebwohl lasher}（GLL）模型精确模仿。它结合了第二和第四阶Legendre互动，其相对相互作用强度为$λ$。对于$λ<-0.3 $，我们观察到{\ it canted}形态，具有$λ$依赖的倾斜角度的形态。对于$λ\ geq-0.3 $，分子对齐得出{\ it均匀}状态。在这两个方案中，粗糙的形态遵守{\ it概括性的动力学缩放}，但是相对于$λ$，缩放函数并不强大。倾斜状态中的结构因子尾巴遵循{\ it porod law}：$ s（k，t）\ sim k^{ - 4} $，这意味着粗糙的动力学是由于界面缺陷的歼灭所致。这是出乎意料的，因为GLL模型的特征是连续阶参数。另一方面，统一的制度表现出预期的{\ it概括的porod decay}：$ s（k，t）\ sim k^{ - 5} $，是{\ it string string defects}散射的特征。最后，域增长遵守{\ it lifShitz-allen-cahn law}：$ l（t）\ sim t^{1/2} $，以所有$λ$的值。我们对小说{\ it Canted}制度的结果与具有定向有序的大量系统相关，例如活跃物质，膜，LC弹性体等。我们希望我们的工作触发刺激其中的调查。
We undertake a comprehensive Monte Carlo (MC) study of the ordering kinetics in nematic liquid crystals (NLCs) in 3-dimensions $(d=3)$ by performing deep quenches from the isotropic $(T>T_c)$ to the nematic $(T<T_c)$ phase. The inter-molecular potential between the nematogens, represented by continuous $O(3)$ spins with inversion symmetry, is accurately mimicked by the {\it generalised Lebwohl Lasher} (GLL) model. It incorporates second and fourth order Legendre interactions, and their relative interaction strength is $λ$. For $λ<-0.3$, we observe {\it canted} morphologies with a $λ$-dependent angle-of-tilt between the neighbouring rod-like molecules. For $λ\geq-0.3$, the molecules align to yield {\it uniform} states. The coarsening morphologies obey {\it generalized dynamical scaling} in the two regimes, but the scaling function is not robust with respect to $λ$. The structure factor tail in the canted regime follows the {\it Porod law}: $S(k,t)\sim k^{-4}$, implying that the coarsening dynamics is due to the annihilation of interfacial defects. This is unexpected, as the GLL model is characterised by a continuous order parameter. The uniform regime on the other hand, exhibits the expected {\it generalized Porod decay}: $S(k,t)\sim k^{-5}$, characteristic of scattering from {\it string defects}. Finally, the domain growth obeys the {\it Lifshitz-Allen-Cahn law}: $L(t)\sim t^{1/2}$ for all values of $λ$. Our results for the novel {\it canted} regime are relevant for a large class of systems with orientational ordering, e.g. active matter, membranes, LC elastomers, etc. We hope that our work triggers-off stimulating investigations in them.
