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标题：Raman fingerprint for semi-metal WTe₂ evolving from bulk to monolayer
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作者：Y. C. Jiang ; J. Gao ; L. Wang 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2016
卷号：6
DOI：10.1038/srep19624
出版社：Springer Nature
摘要：Tungsten ditelluride (WTe₂), a layered transition-metal dichalcogenide (TMD), has recently demonstrated an extremely large magnetoresistance effect, which is unique among TMDs. This fascinating feature seems to be correlated with its special electronic structure. Here, we report the observation of 6 Raman peaks corresponding to the , , , , and phonons, from the 33 Raman-active modes predicted for WTe₂. This provides direct evidence to distinguish the space group of WTe₂ from those of other TMDs. Moreover, the Raman evolution of WTe₂ from bulk to monolayer is clearly revealed. It is interesting to find that the mode, centered at ~109.8 cm^{− 1}, is forbidden in a monolayer, which may be attributable to the transition of the point group from C _2v (bulk) to C _2h (monolayer). Our work characterizes all observed Raman peaks in the bulk and few-layer samples and provides a route to study the physical properties of two-dimensional WTe₂.