Resonance Raman spectroscopy in twisted bilayer graphene
Resonance Raman spectroscopy in twisted bilayer graphene
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DOI：
10.1016/j.ssc.2013.05.015
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发表时间：
2013-12-01
影响因子：
2.1
通讯作者：
Pimenta, M. A.
中科院分区：
文献类型：
--
作者：
Righi, A.;Venezuela, R.;Pimenta, M. A.
本文通过改变入射激光能量在2.54 ~ 4.14 eV之间的变化，研究了不同扭转角度下扭曲双层石墨烯样品的拉曼光谱。光谱显示出许多额外的峰，分为不同的科，每个峰都与具有不同扭转旋转角度的双层石墨烯有关。我们从理论上分析了这些额外峰对激光能量的依赖，考虑了石墨烯布里渊区内部的一组离散波向量，这些波向量激活了特殊的双共振拉曼过程。我们的结果表明，实验光谱和模拟光谱在定性上非常一致，表明这些额外的峰确实归因于石墨烯系统中的umklapp双共振过程。(C) 2013 Elsevier Ltd.版权所有。
In this work we study the Raman spectra of twisted bilayer graphene samples, with different twisting angles, by changing the incident laser energy between 2.54 and 4.14 eV. The spectra exhibit a number of extra peaks, classified in different families, each one associated with bilayer graphenes with different twisting rotational angles. We theoretically analyze the laser energy dependence of these extra peaks considering a set of discrete wavevectors within the interior of the Brillouin zone of graphene, which activate special double-resonance Raman processes. Our result show a nice qualitative agreement between the experimental and simulated spectra, demonstrating that these extra peaks are indeed ascribed to an umklapp double-resonance process in graphene systems. (C) 2013 Elsevier Ltd. All rights reserved.