Interface Coupling in Twisted Multilayer Graphene by Resonant Raman Spectroscopy of Layer Breathing Modes
Interface Coupling in Twisted Multilayer Graphene by Resonant Raman Spectroscopy of Layer Breathing Modes
复制标题
通过层呼吸模式的共振拉曼光谱研究扭曲多层石墨烯中的界面耦合
DOI：
10.1021/acsnano.5b02502
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发表时间：
2015
期刊：
影响因子：
17.1
通讯作者：
Tan Ping-Heng
中科院分区：
文献类型：
--
作者：
Wu Jiang-Bin;Hu Zhi-Xin;Zhang Xin;Han Wen-Peng;Lu Yan;Shi Wei;Qiao Xiao-Fen;Ijiaes Mari;Milana Silvia;Ji Wei;Ferrari Andrea C.;Tan Ping-Heng
拉曼光谱是石墨烯和相关层状材料的主要无损表征工具。切变模式（C）和层呼吸模式（LBM）是由于垂直或平行于其法线的平面的相对运动引起的。这允许人们直接探测多层样品中的层间相互作用。石墨烯和其他二维（2d）晶体可以组合形成各种混合物和异质结构，根据需要创造具有由层间相互作用决定的特性的材料。即使对于单一材料也是如此，其中具有不同相对取向的多层堆叠具有不同的光学和电子性质。在扭曲的多层石墨烯中，由于与由层的相对取向确定的新的光学允许的电子跃迁的共振，C模式有显著的增强。在这里，我们表明，这也适用于LBM，现在可以直接在室温下测量。我们发现，扭曲有一个小的影响LBM，完全不同的情况下的C模式。这意味着两个扭曲层之间的周期性失配主要影响剪切相互作用。我们的工作表明，超低频拉曼光谱是揭示二维杂化和异质结构界面耦合的理想工具。
Raman spectroscopy is the prime nondestructive characterization tool for graphene and related layered materials. The shear (C) and layer breathing modes (LBMs) are due to relative motions of the planes, either perpendicular or parallel to their normal. This allows one to directly probe the interlayer interactions in multilayer samples. Graphene and other two-dimensional (2d) crystals can be combined to form various hybrids and heterostructures, creating materials on demand with properties determined by the interlayer interaction. This is the case even for a single material, where multilayer stacks with different relative orientations have different optical and electronic properties. In twisted multilayer graphene there is a significant enhancement of the C modes due to resonance with new optically allowed electronic transitions, determined by the relative orientation of the layers. Here we show that this applies also to the LBMs, which can be now directly measured at room temperature. We find that twisting has a small effect on LBMs, quite different from the case of the C modes. This implies that the periodicity mismatch between two twisted layers mostly affects shear interactions. Our work shows that ultralow-frequency Raman spectroscopy is an ideal tool to uncover the interface coupling of 2d hybrids and heterostructures.