Spontaneous electric-polarization topology in confined ferroelectric nematics

• Published in: Nature communications Vol. 13; no. 1; pp. 7806 - 12
• Main Authors: Yang, Jidan, Zou, Yu, Tang, Wentao, Li, Jinxing, Huang, Mingjun, Aya, Satoshi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17.12.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 132/124; 639/301/923/919; 639/766/119/996; Chirality; Crystals; Defects; Ferroelectric materials; Ferroelectricity; Humanities and Social Sciences; Liquid crystals; multidisciplinary; Physics; Polarization; Science; Science (multidisciplinary); Thin films; Topology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-35443-7

Topological 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, which appear during the emergence and growth of quasi-2D ferroelectric nematic domains. The chirality can emerge spontaneously in polar textures and can be additionally biased by introducing chiral dopants. Such micrometre-scale polarization textures are the modified electric variants of the magnetic merons. Both experimental and an extended mean-field modelling reveal that the polarization strength plays a dedicated role in determining polarization topology, providing a guide for exploring diverse polar textures in strongly-polarized liquid crystals. Though magnetic and electric states are closely related, many magnetic states cannot find their electric counterparts. Here, the authors report electric variants of merons in thin films of the emerging liquid-matter state, i.e., ferroelectric nematic.