Grzeszczyk M, Gołasa K, Molas M R, Nogajewski K, Zinkiewicz M, Potemski M, Wysmołek A, Babiński A
Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA, 25, Avenue des Martyrs, 38042 Grenoble, France.
Sci Rep. 2018 Dec 10;8(1):17745. doi: 10.1038/s41598-018-35510-4.
We report a study of Raman scattering in few-layer MoTe focused on high-frequency out-of-plane vibrational modes near 291 cm which are associated with the bulk-inactive mode. Our temperature-dependent measurements reveal a double peak structure of the feature related to these modes in the Raman scattering spectra of 4- and 5-layer MoTe. In accordance with literature data, the doublet's lower- and higher-energy components are ascribed to the Raman-active A/ vibrations involving, respectively, only the inner and surface layers. We demonstrate a strong enhancement of the inner mode's intensity at low temperature for 1.91 eV and 1.96 eV laser light excitation which suggests a resonant character of the Raman scattering processes probed under such conditions. A resonance of the laser light with a singularity of the electronic density of states at the M point of the MoTe Brillouin zone is proposed to be responsible for the observed effects.
我们报告了一项关于少层碲化钼中拉曼散射的研究，重点关注在291厘米附近的高频面外振动模式，这些模式与体非活性模式相关。我们的温度相关测量揭示了在4层和5层碲化钼的拉曼散射光谱中，与这些模式相关的特征具有双峰结构。根据文献数据，双峰的低能和高能成分分别归因于仅涉及内层和表面层的拉曼活性A/振动。我们证明了在低温下，对于1.91电子伏特和1.96电子伏特的激光激发，内模式强度有强烈增强，这表明在这种条件下探测的拉曼散射过程具有共振特性。有人提出，激光与碲化钼布里渊区M点处电子态密度的奇点发生共振，是造成观察到的效应的原因。
