Helicity-Resolved Raman Scattering of MoS2, MoSe2, WS2, and WSe2 Atomic Layers
Helicity-Resolved Raman Scattering of MoS2, MoSe2, WS2, and WSe2 Atomic Layers
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DOI：
10.1021/acs.nanolett.5b00092
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发表时间：
2015-04-01
期刊：
影响因子：
10.8
通讯作者：
Yan, Jun
中科院分区：
文献类型：
--
作者：
Chen, Shao-Yu;Zheng, Changxi;Yan, Jun
二维（2D）半导体过渡金属二硫族化合物（TMDCs） （Mo，W）（S,Se）(2)中的双谷简并适用于“谷电子学”，即利用谷自由度存储和操作信息。发光光子螺旋度在这些二维单层晶体中的守恒被广泛认为是载流子谷极化的基准指标。在这里，我们进行了TMDC原子层的螺旋分辨拉曼散射。与发光形成鲜明对比的是，主要的一阶区中心拉曼带，包括低能量呼吸模式和剪切模式以及高能量光学声子，被发现可以维持或完全改变入射光子的螺旋度。除了为表征TMDC原子层提供了有用的工具外，这些实验观察结果还揭示了光子螺旋度和谷极化之间的联系。
The two-fold valley degeneracy in two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs) (Mo,W)(S,Se)(2) is suitable for "valleytronics", the storage and manipulation of information utilizing the valley degree of freedom. The conservation of luminescent photon helicity in these 2D crystal monolayers has been widely regarded as a benchmark indicator for charge carrier valley polarization. Here we perform helicity-resolved Raman scattering of the TMDC atomic layers. In drastic contrast to luminescence, the dominant first-order zone-center Raman bands, including the low energy breathing and shear modes as well as the higher energy optical phonons, are found to either maintain or completely switch the helicity of incident photons. In addition to providing a useful tool for characterization of TMDC atomic layers, these experimental observations shed new light on the connection between photon helicity and valley polarization.