Stacking nonpolar, monolayer materials has emerged as an effective strategy to harvest ferroelectricity in two-dimensional (2D) van der Waals (vdW) materials. At a particular stacking sequence, interlayer charge transfer allows for the generation of out-of-plane dipole components, and the polarization magnitude and direction can be altered by an interlayer sliding. In this work, we use ab initio calculations and demonstrate that in prototype sliding ferroelectrics rhombohedrally-stacked bilayer transition metal dichalcogenides MoS2, the out-of-plane electric polarization can be robustly tuned by photoexcitation in a large range for a given sliding. Such tuning is associated with both a structural origin—i.e., photoinduced structural distortion—and a charge origin, namely, the distribution of photoexcited carriers. We elucidate different roles that photoexcitation plays in modulating sliding ferroelectricity under different light intensities, and we highlight the pivotal role of light in manipulating polarization of 2D vdW materials.

中文翻译：

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滑动铁电体中铁电的大光诱导调谐


堆叠非极性单层材料已成为在二维 （2D） 范德华 （vdW） 材料中收集铁电性的有效策略。在特定的堆叠序列中，层间电荷转移允许产生面外偶极子分量，并且极化幅度和方向可以通过层间滑动来改变。在这项工作中，我们使用了从头开始 的计算，并证明了在原型滑动铁电体菱面体堆叠的双层过渡金属二硫化物 MoS2 中，对于给定的滑动，面外极化可以通过大范围内的光激发进行稳健调整。这种调整与结构起源（即光诱导结构畸变）和电荷起源（即光激发载流子的分布）有关。我们阐明了光激发在不同光强度下调节滑动铁电性的不同作用，并强调了光在操纵二维 vdW 材料偏振中的关键作用。