[论文解读] Deformed states in paraelectric and ferroelectric nematic liquid crystals

Oleg D. Lavrentovich|arXiv (Cornell University)|Mar 22, 2026

Liquid Crystal Research Advancements被引用 0

一句话总结

对分子形状、手性和约束如何在对称性破缺的非极性大分子态和铁电向列相的向列液晶中诱导变形、奇偶性破坏、平行/扭曲/扭曲-弯曲态的综述，包括splay取消效应。

ABSTRACT

Ground states of materials with orientational order ranging from solid ferromagnets and ferroelectrics to liquid crystals often contain spatially varying vector-like order parameter caused by inner factors such as the shape of building units or by the geometry of confinement. This review presents examples of how the shapes, chirality, and polarity of molecules and spatial confinement induce deformed equilibrium and polydomain states with parity breaking, splay, bend, and twist-bend deformations of the order parameter in paraelectric and ferroelectric nematic liquid crystals. Parity breaking results either from chirality of the constituent molecules, as a replacement of energetically costly splay and bend in paraelectric nematics, or in response to depolarization field in the ferroelectric nematic. Both paraelectric and ferroelectric nematics exhibit a splay cancellation effect, in which the elastic and electrostatic energies of splay along one direction are reduced by an additional splay along orthogonal directions.

研究动机与目标

• 解释向列液体中的取向序如何导致时空变化的序参数。
• 总结分子形状、手性和约束如何诱导变形的平衡态与多晶域状态。
• 讨论介电性向列和铁电向列中的奇偶性破坏及splay、bend、twist-bend变形。
• 描述在介电性和铁电性向列中splay取消机制。

提出的方法

• 回顾关于变形向列态的理论与实验发现。
• 总结手性与极性如何稳定变形的机理。
• 解释铁电向列中的去极化场效应和splay能量考量。
• 讨论约束和分子几何在产生多晶域态中的作用。

实验结果

研究问题

• RQ1 在介电性和铁电性向列中推动奇偶性破坏变形的机制是什么？
• RQ2 手性与极性如何影响splay、bend和twist-bend扭曲？
• RQ3 splay取消效应是什么，它在这些材料中如何表现？
• RQ4 约束与分子几何如何促成变形的平衡态与多晶域态？

主要发现

• 介电性向列和铁电性向列在呈现变形的平衡态和多晶域态方面存在相似性。
• 奇偶性破坏可来自分子手性，或来自对铁电向列中去极化场的响应。
• splay取消在沿正交方向发生splay时降低弹性和静电能。
• 实例显示由形状、手性和约束驱动的一系列splay、bend和twist-bend变形。