Birth and annihilation of topological defects on the nematic–isotropic interface during droplet coalescence

In our work, we for the first time observed simultaneous birth and subsequent annihilation of two types of defects on nematic–isotropic interface: point boojums and localised equatorial defects. The investigations were made in the two-phase nematic–isotropic region in nematic droplets with conical boundary conditions. We found a new type of localized defects formed from equatorial ring defects in confined geometry of planar optical cells. During coalescence of nematic droplets, we observed formation of four antipodes of boojums and localised equatorial defects, followed by their pairwise annihilation with existing defects. The dynamics of defect annihilation was investigated.

在本研究中，我们首次在向列相-各向同性相界面上观测到两类缺陷的同步生成与后续湮灭：点布居姆缺陷（point boojums）与局域赤道缺陷。实验观测在具备锥形边界条件的向列相液滴的向列相-各向同性两相区域内开展。我们在平面光学盒的受限几何结构中，发现了一类由赤道环缺陷演化形成的新型局域缺陷。在向列相液滴融合过程中，我们观测到布居姆缺陷与局域赤道缺陷的四个对跖位点生成，随后它们与现存缺陷发生成对湮灭。我们对缺陷湮灭的动力学过程进行了研究。