论文标题

受限制的铁电鸟类的自发电偏拓扑

Spontaneous electric-polarization topology in confined ferroelectric nematics

论文作者

Yang, Jidan, Zou, Yu, Tang, Wentao, Li, Jinxing, Huang, Mingjun, Aya, Satoshi

论文摘要

拓扑旋转和极性纹理使人们在物理和技术领域的不同领域着迷。但是,观测值在磁性和固态铁电系统中受到限制。铁电列是第一个具有空间分布极化场的可能性的液态铁电。与传统的磁或结晶系统相反,各向异性液晶相互作用可以与极化对应物竞争,从而在低估其相互作用和由此产生的拓扑结构时面临挑战。在这里,我们在准2D铁电列域的出现和生长过程中发现了手性偏振类结构,这些结构通过荧光共聚焦极化显微镜和第二个谐波生成显微镜可视化。这种微米尺度的极化纹理是磁性梅隆的修改电动变体。与仅由弹性驱动的常规液晶纹理不同,极化场将其他拓扑结构(例如,从头到尾不对称)置于系统,并导致各种以前未知的极性拓扑模式。手性可以自发地出现在极性纹理中,并且可以通过引入手性掺杂剂来偏见。铁电势迹象的扩展平均模型表明,系统的极化强度在确定极化拓扑中起着专门的作用,为探索强质液体晶体中各种极性纹理提供了指南。

Topological spin and polar textures have fascinated people in different areas of physics and technologies. However, the observations are limited in magnetic and solid-state ferroelectric systems. Ferroelectric nematic is the first liquid-state ferroelectric that would carry many possibilities of spatially distributed polarization fields. Contrary to traditional magnetic or crystalline systems, anisotropic liquid crystal interactions can compete with the polarization counterparts, thereby setting a challenge in understating their interplays and the resultant topologies. Here, we discover chiral polarization meron-like structures during the emergence and growth of quasi-2D ferroelectric nematic domains, which are visualized by fluorescence confocal polarizing microscopy and second harmonic generation microscopies. Such micrometre-scale polarization textures are the modified electric variants of the magnetic merons. Unlike the conventional liquid crystal textures driven solely by the elasticity, the polarization field puts additional topological constraints, e.g., head-to-tail asymmetry, to the systems and results in a variety of previously unidentified polar topological patterns. The chirality can emerge spontaneously in polar textures and can be additionally biased by introducing chiral dopants. An extended mean-field modelling for the ferroelectric nematics reveals that the polarization strength of systems plays a dedicated role in determining polarization topology, providing a guide for exploring diverse polar textures in strongly-polarized liquid crystals.

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