Interface Coupling in Twisted Multilayer Graphene by Resonant Raman Spectroscopy of Layer Breathing Modes

详细信息    查看全文

• 作者：Jiang-Bin Wu ; Zhi-Xin Hu ; Xin Zhang ; Wen-Peng Han ; Yan Lu ; Wei Shi ; Xiao-Fen Qiao ; Mari Iji盲s ; Silvia Milana ; Wei Ji ; Andrea C. Ferrari ; Ping-Heng Tan
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：July 28, 2015
• 年：2015
• 卷：9
• 期：7
• 页码：7440-7449
• 全文大小：833K
• ISSN：1936-086X

文摘

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.