Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China.
School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang, 110016, China.
Nat Commun. 2023 Jun 8;14(1):3376. doi: 10.1038/s41467-023-39169-y.
The period of polar domain (d) in ferroics was commonly believed to scale with corresponding film thicknesses (h), following the classical Kittel's law of d ∝ [Formula: see text]. Here, we have not only observed that this relationship fails in the case of polar skyrmions, where the period shrinks nearly to a constant value, or even experiences a slight increase, but also discovered that skyrmions have further persisted in [(PbTiO)/(SrTiO)] ultrathin superlattices. Both experimental and theoretical results indicate that the skyrmion periods (d) and PbTiO layer thicknesses in superlattice (h) obey the hyperbolic function of d = Ah + [Formula: see text] other than previous believed, simple square root law. Phase-field analysis indicates that the relationship originates from the different energy competitions of the superlattices with PbTiO layer thicknesses. This work exemplified the critical size problems faced by nanoscale ferroelectric device designing in the post-Moore era.
铁电体中的极性畴（d）周期通常被认为与相应的薄膜厚度（h）成正比，遵循经典的 Kittel 定律 d∝[公式：见正文]。在这里，我们不仅观察到这种关系在极性斯格明子的情况下失效，其中周期几乎收缩到一个常数，甚至略有增加，而且还发现斯格明子在[(PbTiO)/(SrTiO)]超晶格中进一步存在。实验和理论结果表明，斯格明子周期（d）和超晶格中的 PbTiO 层厚度（h）遵循双曲线关系 d=Ah+[公式：见正文]，而不是之前认为的简单平方根定律。相场分析表明，这种关系源于具有不同 PbTiO 层厚度的超晶格的不同能量竞争。这项工作说明了在摩尔时代之后纳米级铁电器件设计所面临的临界尺寸问题。
