Magnetic and electric dipoles have similar symmetry and are therefore expected to exhibit many common structures. However, despite frequent reports of various spin textures composed of magnetic dipoles, investigations on long-range ordered electric dipoles have been scarce, until recently. Here we discover spontaneous toroidal polar topology in an emerging ferroelectric liquid state with polarization helices, dubbed ‘helielectric nematic’. The interplay between liquid-crystal elasticity and polar interactions results in a continuous in-plane rotation of the polarization, producing a periodic toroidal assembly. In partial analogy with magnetism, the neighbouring toroidal domains are separated by circularly shaped domain walls. The local polarization switching enables unique shrinkage and expansion dynamics of the toroidal domains. The discovery provides opportunities for developing designable and switchable ferroelectric-liquid-matter opto-electronics.

磁偶极子和电偶极子具有相似的对称性，因此预计会表现出许多常见的结构。然而，尽管经常报道由磁偶极子组成的各种自旋结构，但直到最近，对长程有序电偶极子的研究还很少。在这里，我们发现了一种新兴的铁电液体状态下的自发环形极性拓扑，具有极化螺旋，被称为“日电向列”。液晶弹性和极性相互作用之间的相互作用导致偏振的连续面内旋转，产生周期性的环形组件。与磁性部分类似，相邻的环形磁畴由圆形磁畴壁分隔开。局部偏振切换实现了环形域独特的收缩和扩张动力学。这一发现为开发可设计和可切换的铁电液体光电子学提供了机会。