The European Physical Journal E ( IF 1.8 ) Pub Date : 2022-09-20 , DOI: 10.1140/epje/s10189-022-00226-x Saša Harkai 1 , Samo Kralj 2, 3
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Topological defects (TDs) are a consequence of symmetry breaking phase transitions and are ubiquitous in nature. An ideal testbed for their study are liquid crystals (LCs) owing to their large response to external stimuli and their large electrical and optical anisotropies. In this paper, we perform numerical simulations of topological defects of \(\left| k \right| = 1/2\) or \(\left| k \right| = 1\) enforced by the confining boundary. We use the Landau–de Gennes phenomenological model in terms of the tensor nematic order parameter and the Jones beam propagation model to simulate polarized optical microscopy images. We demonstrate the structure of closed disclination loops near the boundary known as boojums that can be topologically charged or chargeless. We show that pairs of chargeless disclination loops can interact repulsively or attractively depending on if they are arranged parallel or antiparallel, respectively. Sufficiently closely spaced antiparallel pairs can rewire while parallel pairs simply exhibit stronger bending due to the repulsion.
Graphical abstract
中文翻译：
向列向错的结构转变
拓扑缺陷 (TD) 是对称破坏相变的结果，并且在自然界中无处不在。他们研究的理想测试平台是液晶 (LC)，因为它们对外部刺激的反应大以及它们的电和光学各向异性大。在本文中，我们对\(\left| k \right| = 1/2\)或\(\left| k \right| = 1\)的拓扑缺陷进行了数值模拟由约束边界强制执行。我们根据张量向列序参数和琼斯光束传播模型使用 Landau-de Gennes 唯象模型来模拟偏振光学显微镜图像。我们展示了边界附近的闭合向错环的结构，称为 boojums，可以是拓扑带电或不带电的。我们表明，成对的无电荷向错环可以相互排斥或相互吸引，具体取决于它们是平行排列还是反平行排列。间隔足够近的反平行线对可以重新布线，而平行线对由于排斥而仅仅表现出更强的弯曲。
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