On electrically tunable stacking domains and ferroelectricity in moire superlattices
On electrically tunable stacking domains and ferroelectricity in moire superlattices
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DOI：
10.1038/s41699-021-00281-6
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发表时间：
2022-01-17
影响因子：
9.7
通讯作者：
Remez, Benjamin
中科院分区：
文献类型：
--
作者：
Bennett, Daniel;Remez, Benjamin
在莫尔超晶格中，由于层间范德华作用力和层内弹性力的竞争而形成的堆积域，可以被认为是由于不具有中心对称性的双层膜中的局域自发极化而形成的极化域。我们提出了一个理论模型，该模型描述了外加电场对磁畴结构的影响。自发极化与场的耦合导致了磁畴的不均匀弛豫，在非零场下超晶格中出现了对莫尔周期敏感的净极化。我们发现，介电响应降低了堆积能，导致所有双层膜中的磁区变得更软。然后，我们在我们的模型中讨论了最近对铁电性的观察。
It is well known that stacking domains form in moire superlattices due to the competition between the interlayer van der Waals forces and intralayer elastic forces, which can be recognized as polar domains due to the local spontaneous polarization in bilayers without centrosymmetry. We propose a theoretical model which captures the effect of an applied electric field on the domain structure. The coupling between the spontaneous polarization and field leads to uneven relaxation of the domains, and a net polarization in the superlattice at nonzero fields, which is sensitive to the moire period. We show that the dielectric response to the field reduces the stacking energy and leads to softer domains in all bilayers. We then discuss the recent observations of ferroelectricity in the context of our model.