Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 30123-970, Brazil.
Phys Rev Lett. 2015 Apr 3;114(13):136403. doi: 10.1103/PhysRevLett.114.136403. Epub 2015 Apr 2.
This work describes a resonance Raman study performed on samples with one, two, and three layers (1L, 2L, 3L), and bulk MoS2, using more than 30 different laser excitation lines covering the visible range, and focusing on the intensity of the two most pronounced features of the Raman scattering spectrum of MoS2 (E2g(1) and A1g bands). The Raman excitation profiles of these bands were obtained experimentally, and it is found that the A1g feature is enhanced when the excitation laser is in resonance with A and B excitons of MoS2, while the E2g1 feature is shown to be enhanced when the excitation laser is close to 2.7 eV. We show from the symmetry analysis of the exciton-phonon interaction that the mode responsible for the E2g(1) resonance is identified as the high energy C exciton recently predicted [D. Y. Qiu, F. H. da Jornada, and S. G. Louie, Phys. Rev. Lett. 111, 216805 (2013)].
这项工作描述了对具有一层、两层和三层（1L、2L、3L）以及块状 MoS2 的样品进行的共振拉曼研究，使用了超过 30 条不同的激光激发线，涵盖了可见范围，并重点关注了 MoS2 拉曼散射光谱中两个最明显的特征的强度（E2g(1) 和 A1g 带）。这些带的 Raman 激发轮廓是通过实验获得的，结果发现，当激发激光与 MoS2 的 A 和 B 激子共振时，A1g 特征得到增强，而当激发激光接近 2.7 eV 时，E2g1 特征被证明得到增强。我们从激子-声子相互作用的对称性分析中表明，负责 E2g(1) 共振的模式被确定为最近预测的高能 C 激子[D. Y. Qiu、F. H. da Jornada 和 S. G. Louie，Phys. Rev. Lett. 111, 216805 (2013)]。
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