Giant Second Harmonic Generation in Supertwisted WS2 Spirals Grown in Step-Edge Particle-Induced Non-Euclidean Surfaces,ACS Nano

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Giant Second Harmonic Generation in Supertwisted WS2 Spirals Grown in Step-Edge Particle-Induced Non-Euclidean Surfaces
ACS Nano ( IF 15.8 ) Pub Date : 2024-08-08 , DOI: 10.1021/acsnano.4c02807
Tong Tong _{1,

2} , Ruijie Chen ₁ , Yuxuan Ke ₃ , Qian Wang ₁ , Xinchao Wang ₁ , Qinjun Sun ₂ , Jie Chen ₁ , Zhiyuan Gu ₁ , Ying Yu ₁ , Hongyan Wei ₁ , Yuying Hao ₁ , Xiaopeng Fan ₁ , Qing Zhang ₃

Affiliation

In moiré crystals resulting from the stacking of twisted two-dimensional (2D) layered materials, a subtle adjustment in the twist angle surprisingly gives rise to a wide range of correlated optical and electrical properties. Herein, we report the synthesis of supertwisted WS₂ spirals and the observation of giant second harmonic generation (SHG) in these spirals. Supertwisted WS₂ spirals featuring different twist angles are synthesized on a Euclidean or step-edge particle-induced non-Euclidean surface using carefully designed water-assisted chemical vapor deposition. We observed an oscillatory dependence of SHG intensity on layer number, attributed to atomically phase-matched nonlinear dipoles within layers of supertwisted spiral crystals where inversion symmetry is restored. Through an investigation into the twist angle evolution of SHG intensity, we discovered that the stacking model between layers plays a crucial role in determining the nonlinearity, and the SHG signals in supertwisted spirals exhibit enhancements by a factor of 2 to 136 when compared with the SHG of the single-layer structure. These findings provide helpful perspectives on the rational growth of 2D twisted structures and the implementation of twist angle adjustable endowing them great potential for exploring strong coupling correlation physics and applications in the field of twistronics.

中文翻译：

阶梯边缘粒子诱导非欧几里得表面中生长的超扭曲 WS2 螺旋中的巨大二次谐波产生

在由扭曲的二维 (2D) 层状材料堆叠而成的莫尔晶体中，扭曲角度的细微调整令人惊讶地产生了广泛的相关光学和电学特性。在此，我们报告了超扭曲_WS2螺旋的合成以及在这些螺旋中观察到的巨大二次谐波产生（SHG）。使用精心设计的水辅助化学气相沉积，在欧几里德或阶梯边缘粒子诱导的非欧几里德表面上合成具有不同扭转角的超扭转 WS ₂螺旋。我们观察到倍频强度对层数的振荡依赖性，归因于超扭曲螺旋晶体层内原子相位匹配的非线性偶极子，其中反转对称性得以恢复。通过对倍频强度扭转角演变的研究，我们发现层间的堆叠模型在确定非线性方面起着至关重要的作用，并且超扭转螺旋中的倍频信号与倍频信号相比表现出2至136倍的增强的单层结构。这些发现为二维扭曲结构的合理生长和扭曲角度可调的实现提供了有益的视角，使其在探索强耦合相关物理及其在扭曲电子学领域的应用方面具有巨大的潜力。

更新日期：2024-08-08

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