Sliding ferroelectricity in 2D van der Waals materials: Related physics and future opportunities
Sliding ferroelectricity in 2D van der Waals materials: Related physics and future opportunities
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DOI：
10.1073/pnas.2115703118
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发表时间：
2021-12-14
影响因子：
11.1
通讯作者：
Li, Ju
中科院分区：
文献类型：
--
作者：
Wu, Menghao;Li, Ju
在铁电性发现100周年之际，人们提出了所谓的滑动铁电性，并在最近的一系列实验中得到了证实，引起了人们的极大兴趣。这种铁电性广泛存在，并且仅存在于二维（2D）货车范德华堆叠层中，其中垂直电极化通过面内层间滑动切换。相反，层间滑动和“ripplocation”畴壁可以由外部垂直电场驱动。2D货车德瓦尔斯层的层内刚度和层间滑动性的独特组合极大地促进了这种切换，同时在环境条件下仍然保持环境和机械鲁棒性。从这个角度，我们讨论了这种行为的进展和未来的机会。总结了这种铁电性的起源和判断其存在的一般规律，其中垂直堆叠顺序是形成这种铁电性的关键。这一发现将二维铁电体从极少数候选材料扩展到大多数已知的二维材料。它们的低开关势垒能够以低能耗实现高速数据写入。相关的物理如莫尔铁电性，铁电非线性异常霍尔效应，和多铁性耦合进行了讨论。对于二维谷电子学，非平凡能带拓扑和超导性，它们通过某些堆叠或莫尔铁电性与滑动铁电性的可能耦合也值得关注。我们对这一新兴领域目前面临的挑战进行了批判性评论。
Near the 100th anniversary of the discovery of ferroelectricity, so-called sliding ferroelectricity has been proposed and confirmed recently in a series of experiments that have stimulated remarkable interest. Such ferroelectricity exists widely and exists only in two-dimensional (2D) van der Waals stacked layers, where the vertical electric polarization is switched by in-plane interlayer sliding. Reciprocally, interlayer sliding and the "ripplocation" domain wall can be driven by an external vertical electric field. The unique combination of intralayer stiffness and interlayer slipperiness of 2D van der Waals layers greatly facilitates such switching while still maintaining environmental and mechanical robustness at ambient conditions. In this perspective, we discuss the progress and future opportunities in this behavior. The origin of such ferroelectricity as well as a general rule for judging its existence are summarized, where the vertical stacking sequence is crucial for its formation. This discovery broadens 2D ferroelectrics from very few material candidates to most of the known 2D materials. Their low switching barriers enable high-speed data writing with low energy cost. Related physics like Moire ferroelectricity, the ferroelectric nonlinear anomalous Hall effect, and multiferroic coupling are discussed. For 2D valleytronics, nontrivial band topology and superconductivity, their possible couplings with sliding ferroelectricity via certain stacking or Moire ferroelectricity also deserve interest. We provide critical reviews on the current challenges in this emerging area.