Spherical ferroelectric domains, such as electrical bubbles, polar skyrmion bubbles and hopfions, share a single and unique feature—their homogeneously polarized cores are surrounded by a vortex ring of polarization whose outer shells form a spherical domain boundary. The resulting polar texture, typical of three-dimensional topological solitons, has an entirely new local symmetry characterized by a high polarization and strain gradients. Consequently, spherical domains represent a different material system of their own with emergent properties drastically different from that of their surrounding medium. Examples of new functionalities inherent to spherical domains include chirality, optical response, negative capacitance and giant electromechanical response. These characteristics, particularly given that the domains naturally have an ultrafine scale, offer new opportunities in high-density and low-energy nanoelectronic technologies. This Perspective gives an insight into the complex polar structure and physical origin of these spherical domains, which facilitates the understanding and development of spherical domains for device applications.

球形铁电畴，如电泡、极地斯格明子泡和跳跃离子，都有一个独特的特征——它们均匀极化的核心被极化涡环包围，其外壳形成球形畴边界。由此产生的极性纹理，典型的三维拓扑孤子，具有以高极化和应变梯度为特征的全新局部对称性。因此，球形域代表了它们自己的不同材料系统，其涌现特性与周围介质的特性截然不同。球域固有的新功能示例包括手性、光学响应、负电容和巨大的机电响应。这些特点，特别是考虑到域自然具有超细尺度，为高密度和低能量纳米电子技术提供了新的机会。该观点深入了解了这些球域的复杂极性结构和物理起源，这有助于理解和开发用于设备应用的球域。