Real-Time Observation of Interlayer Vibrations in Bilayer and Few-Layer Graphene
Real-Time Observation of Interlayer Vibrations in Bilayer and Few-Layer Graphene
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DOI：
10.1021/nl401713h
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发表时间：
2013-10-01
期刊：
影响因子：
10.8
通讯作者：
Heinz, Tony F.
中科院分区：
文献类型：
--
作者：
Boschetto, Davide;Malard, Leandro;Heinz, Tony F.
我们报道了对双层石墨烯和少层石墨烯的层间剪切模式的实时观察，对应于石墨烯平面的横向振荡。利用飞秒泵浦-探测技术，我们直接在时间域中跟踪了这种振动模式的相干振荡。对于层间模式，剪切模式频率表现出强烈的和系统的依赖于层的数目，从体限值的1.32太赫兹到双层石墨烯的0.85太赫兹。我们通过比较不同衬底支撑的石墨烯薄膜和悬浮在自由空间中的石墨烯薄膜的响应，探索了与外部环境的相互作用对这种振动模式的作用。没有观察到明显的频移。
We report real-time observation of the interlayer shearing mode, corresponding; to the lateral oscillation of graphene planes, for bi- and few-layer graphene. Using a femtosecond pump-probe technique, we have followed coherent oscillations of this vibrational mode directly in the time domain. The shearing-mode frequency, as expected for an interlayer mode, exhibits a strong and systematic dependence on the number of layers, varying from 1.32 THz for the bulk limit to 0.85 THz for bilayer graphene. We explored the role of interactions with the external environment on this vibrational mode by comparing the response observed for graphene layers supported by different substrates and suspended in free space. No significant frequency shifts were observed.