Anomalous Polarized Raman Scattering and Large Circular Intensity Differential in Layered Triclinic ReS2.
Anomalous Polarized Raman Scattering and Large Circular Intensity Differential in Layered Triclinic ReS2.
复制标题
DOI：
10.1021/acsnano.7b05321
复制
发表时间：
2017-10
期刊：
影响因子：
17.1
通讯作者：
Shishu Zhang;Nannan Mao;N. Zhang;Juanxia Wu;L. Tong;Jin Zhang
中科院分区：
文献类型：
--
作者：
Shishu Zhang;Nannan Mao;N. Zhang;Juanxia Wu;L. Tong;Jin Zhang
晶体的拉曼张量是其极化率张量的导数，并且取决于晶体的对称性和拉曼活性振动模式。特定模式的强度由拉曼选择规则确定，该规则涉及拉曼张量和偏振配置。对于各向异性二维层状晶体，偏振拉曼散射已被用来揭示晶体取向。然而，由于其复杂的拉曼张量和光学双折射，三斜晶系二维晶体的偏振拉曼散射尚未得到很好的研究。本文报道了二维层状三斜晶系二硫化铼（ReS 2）的反常偏振拉曼散射，发现不同厚度的ReS 2的拉曼散射具有较大的圆强度差（CID）. CID的起源和偏振拉曼散射中的反常行为归因于非零非对角拉曼张量元的出现和光学双折射引起的相位因子。这为确定三斜层状材料的垂直取向提供了一种方法。这些发现有助于进一步理解低对称性二维材料中的拉曼散射过程，并可能预示着二维材料在手性识别中的重要应用。
The Raman tensor of a crystal is the derivative of its polarizability tensor and is dependent on the symmetries of the crystal and the Raman-active vibrational mode. The intensity of a particular mode is determined by the Raman selection rule, which involves the Raman tensor and the polarization configurations. For anisotropic two-dimensional (2D) layered crystals, polarized Raman scattering has been used to reveal the crystalline orientations. However, due to its complicated Raman tensors and optical birefringence, the polarized Raman scattering of triclinic 2D crystals has not been well studied yet. Herein, we report the anomalous polarized Raman scattering of 2D layered triclinic rhenium disulfide (ReS2) and show a large circular intensity differential (CID) of Raman scattering in ReS2 of different thicknesses. The origin of CID and the anomalous behavior in polarized Raman scattering were attributed to the appearance of nonzero off-diagonal Raman tensor elements and the phase factor owing to optical birefringence. This can provide a method to identify the vertical orientation of triclinic layered materials. These findings may help to further understand the Raman scattering process in 2D materials of low symmetry and may indicate important applications in chiral recognition by using 2D materials.