Chiral materials possess broken inversion and mirror symmetry and show great potential in the application of next-generation optic, electronic, and spintronic devices. Two-dimensional (2D) chiral crystals have planar chirality, which is nonsuperimposable on their 2D enantiomers by any rotation about the axis perpendicular to the substrate. The degree of freedom to construct vertical stacking of 2D monolayer enantiomers offers the possibility of chiral manipulation for designed properties by creating multilayers with either a racemic or enantiomerically pure stacking order. However, the rapid recognition of the relative proportion of two enantiomers becomes demanding due to the complexity of stacking orders of 2D chiral crystals. Here, we report the unambiguous identification of racemic and enantiomerically pure stackings for layered ReSe₂ and ReS₂ using circular polarized Raman spectroscopy. The chiral Raman response is successfully manipulated by the enantiomer proportion, and the stacking orders of multilayer ReSe₂ and ReS₂ can be completely clarified with the help of second harmonic generation and scanning transmission electron microscopy measurements. Finally, we trained an artificial intelligent Spectra Classification Assistant to predict the chirality and the complete crystallographic structures of multilayer ReSe₂ from a single circular polarized Raman spectrum with the accuracy reaching 0.9417 ± 0.0059.

中文翻译：

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通过机器学习实现二维三斜晶体的手性堆积识别


手性材料具有破缺反转和镜面对称性，在下一代光学、电子和自旋电子器件的应用中显示出巨大的潜力。二维 (2D) 手性晶体具有平面手性，通过绕垂直于基底的轴的任何旋转都不能叠加在其 2D 对映体上。构建二维单层对映体垂直堆叠的自由度提供了通过创建具有外消旋或对映体纯堆叠顺序的多层来对设计特性进行手性操作的可能性。然而，由于二维手性晶体堆叠顺序的复杂性，快速识别两种对映体的相对比例变得要求很高。在这里，我们报告了使用圆偏振拉曼光谱明确鉴定了层状 ReSe ₂ 和 ReS ₂ 的外消旋和对映体纯堆叠。通过对映体比例成功控制了手性拉曼响应，借助二次谐波产生和扫描透射电子，可以完全阐明多层ReSe ₂ 和ReS ₂ 的堆叠顺序显微镜测量。最后，我们训练了人工智能光谱分类助手，从单个圆偏振拉曼光谱预测多层ReSe ₂ 的手性和完整​​晶体结构，精度达到0.9417 ± 0.0059。