Van der Waals (vdW) assembly of layered materials is a promising paradigm for creating electronic and optoelectronic devices with novel properties. Ferroelectricity in vdW layered materials could enable nonvolatile memory and low-power electronic and optoelectronic switches, but to date, few vdW ferroelectrics have been reported, and few in-plane vdW ferroelectrics are known. We report the discovery of in-plane ferroelectricity in a widely investigated vdW layered material, β'-In₂Se₃. The in-plane ferroelectricity is strongly tied to the formation of one-dimensional superstructures aligning along one of the threefold rotational symmetric directions of the hexagonal lattice in the c plane. Surprisingly, the superstructures and ferroelectricity are stable to 200°C in both bulk and thin exfoliated layers of In₂Se₃. Because of the in-plane nature of ferroelectricity, the domains exhibit a strong linear dichroism, enabling novel polarization-dependent optical properties.

中文翻译：

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范德华斯In2Se3中的室温面内铁电。

范德华（vdW）分层材料的组装是一种有前途的范例，可用于创建具有新颖特性的电子和光电设备。vdW层状材料中的铁电可以实现非易失性存储器以及低功率电子和光电开关，但是迄今为止，很少有vdW铁电体被报道，而且平面内vdW铁电体也为人们所知。我们报告在平面铁电性的广泛研究范德华发现分层素材，β'-在₂硒₃。平面内铁电与沿c六角形晶格的三重旋转对称方向之一对齐的一维超结构的形成紧密相关。飞机。出乎意料的是，在In ₂ Se _3的块状和薄层剥离层中，上部结构和铁电性均稳定至200°C 。由于铁电的平面内性质，这些畴表现出很强的线性二向色性，从而实现了新颖的偏振相关光学特性。