Polar topological phases in oxide superlattices attracted significant attention due to their unique properties. Previous work revealed that a polar vortex and polar skyrmions exist in (PTO)/(STO) superlattices under different elastic constraints, i.e., on different substrates. Here, our phase-field simulation demonstrates that manipulating the PTO and STO layers’ thickness can control the effective screening provided by STO and the depolarization degree in PTO, thus switching the system among the polar skyrmions, vortex labyrinth, or paraelectric phase without changing elastic constraints. Additionally, reducing the STO thickness creates interlayer coupling among PTO layers, generating the long-range order of topological phases within superlattices. Furthermore, we construct a PTO–STO thickness topological phase diagram. These findings offer insights into the polar topological phases’ formation in oxide superlattices, elucidating the roles of ferroelectric and paraelectric layers in their formation.

中文翻译：

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通过控制氧化物超晶格中的有效屏蔽和去极化来调整拓扑相位


氧化物超晶格中的极性拓扑相由于其独特的性质而引起了广泛的关注。先前的工作表明，在不同的弹性约束下，即在不同的基底上，（PTO）/（STO）超晶格中存在极涡和极斯格明子。在这里，我们的相场模拟表明，操纵PTO和STO层的厚度可以控制STO提供的有效屏蔽和PTO的去极化程度，从而在不改变弹性的情况下在极性斯格明子、涡旋迷宫或顺电相之间切换系统限制。此外，减少 STO 厚度会在 PTO 层之间产生层间耦合，从而在超晶格内生成拓扑相的长程有序。此外，我们构建了 PTO-STO 厚度拓扑相图。这些发现为氧化物超晶格中极性拓扑相的形成提供了见解，阐明了铁电层和顺电层在其形成中的作用。