Topologically nontrivial polar structures are not only attractive for high-density data storage, but also for ultralow power microelectronics thanks to their exotic negative capacitance. The vast majority of polar structures emerging naturally in ferroelectrics, however, are topologically trivial, and there are enormous interests in artificially engineered polar structures possessing nontrivial topology. Here we demonstrate reconstruction of topologically trivial strip-like domain architecture into arrays of polar vortex in (PbTiO₃)₁₀/(SrTiO₃)₁₀ superlattice, accomplished by fabricating a cross-sectional lamella from the superlattice film. Using a combination of techniques for polarization mapping, atomic imaging, and three-dimensional structure visualization supported by phase field simulations, we reveal that the reconstruction relieves biaxial epitaxial strain in thin film into a uniaxial one in lamella, changing the subtle electrostatic and elastostatic energetics and providing the driving force for the polar vortex formation. The work establishes a realistic strategy for engineering polar topologies in otherwise ordinary ferroelectric superlattices.

拓扑非平凡的极性结构不仅对高密度数据存储具有吸引力，而且由于其奇特的负电容，对超低功耗微电子产品也很有吸引力。然而，铁电体中自然出现的绝大多数极性结构在拓扑上都是微不足道的，并且对具有非平凡拓扑的人工工程极性结构产生了巨大的兴趣。在这里，我们展示了在 (PbTiO ₃ ) ₁₀ /(SrTiO ₃ ) ₁₀中将拓扑微不足道的条状域结构重建为极涡阵列超晶格，通过从超晶格薄膜制造横截面薄片来实现。使用偏振映射、原子成像和相场模拟支持的三维结构可视化技术的组合，我们揭示了重建将薄膜中的双轴外延应变减轻为薄片中的单轴外延应变，改变了微妙的静电和弹性静力学能量并为极地涡旋的形成提供驱动力。这项工作为在其他普通铁电超晶格中设计极性拓扑建立了一种现实的策略。