[黄昆论坛]第373期:Energy Harvesting by Spin Current
[黄昆论坛]第372期:Enhancement of Light Color Conversion through Nanoscal...
[黄昆论坛]第371期: 光力学中的拓扑和非互易动力学
[黄昆论坛]第370期:Recent Advances of 2D Metal-Complex Nanosheets
[黄昆论坛]第369期:High-speed optoelectronics for underwater optical wire...
[黄昆论坛]第368期:The Development of Low Noise Avalanche Photodiodes
[黄昆论坛]第367期:氧化钛纳米棒的制备以及在染料敏化太阳电池中的应用
[黄昆论坛]第366期:Valleytronics and correlated phase probed by interlaye...
[黄昆论坛]第365期:低维纳米材料的极化激元及其增强红外光谱研究
[黄昆论坛]第364期:微纳光子的高效操控与室温量子态
官方微信
友情链接

[黄昆论坛]第327期:Double-Resonant Raman Processes in Single Layer Graphene, Carbon Nanotubes and Twisted Bilayer Graphene

2018-08-31

报告题目:Double-Resonant Raman Processes in Single Layer Graphene, Carbon Nanotubes and Twisted Bilayer Graphene

报告人:Prof. Pedro Venezuela (Instituto de Física, Universidade Federal Fluminense, Niterói, Brazil)

报告时间:2018年9月3日 下午2:00

报告地点:中国科学院半导体研究所2号楼303A

Abstract: Lowest-order Raman processes, for instance the G band in graphene, correspond to the scattering with a zero-momentum phonon (q = 0). Graphene and graphitic materials present other lines, due to higher-order processes, which are usually interpreted in terms of the so-called double-resonance (DR) mechanism. The DR mechanism is used to interpret RamanD band and 2D band in graphene. We have developed a methodology, based on Density Functional theory, to simulate the DR processes in graphene[1].
Here we show that the Raman bands related to DR processes are a powerful tool to probe the structural, electronic and vibrational properties of graphitic materials. We will focus in three different systems: monolayer graphene, carbon nanotubes and twisted bilayer graphene.In monolayer graphene, the observed 2D line width contains valuable information on strain variations in graphene on length scales far below the laser spot size, that is, on the nanometer-scale[2], which is a good and easily accessible quantity for classifying the crystalline quality, nanometer-scale flatness as well as local electronic properties of graphene.Concerning carbon nanotubes, we have studied the D and 2D Raman bands of chirality enriched samples[3]. We show that each single-chirality nanotube exhibits a series of non-dispersive D and 2D Raman peaks, which are not necessarily enhanced by resonances with optical transitions between van Hove singularities. Our results provide a complete explanation of the DR Raman spectrum, including the D and 2D bands, at the specificity level of a single-chirality nanotube, and allow the correct interpretation of the DR spectra of carbon nanotubes in samples containing a distribution of different (n, m) nanotube species.Finally, for twisted bilayer graphene[4], we discuss the possibility of distinguishing intralayer and interlayer electron-phonon (el-ph) interactions and of probing the intralayer process in graphene/h-BN. In the intralayer process, the el-ph scattering occurs in a single graphene layer and the other layer (graphene or h-BN) imposes a periodic potential that back scatters the excited electron, whereas for the interlayer process the el-ph scattering occurs between states in the Dirac cones of adjacent graphene layers. Our methodology of using Raman spectroscopy to probe different types of el-ph interactions can be extended to study any kind of graphene-based heterostructure.
[1] Venezuela P, Lazzeri M and Mauri F, Phys. Rev. B 2011; 84: 035433.
[2] Neumann C, Reichardt S, Venezuela P, Drgeler M, Banszerus L, Schmitz M, Watanabe K, Taniguchi T, Mauri F, Beschoten B, Rotkin SV and Stampfer C, Nat. Comm. 2015; 6: 8429.
[3] Moura LG, Moutinho MVO, Venezuela P, Mauri F, Righi A, Strano MS, Fantini C, Pimenta MA, Carbon 2017; 111: 41.
[4] Eliel GSN, Moutinho MVO, Gadelha AC, Righi A, Campos L, Ribeiro HB, Chiu P-W , Watanabe K, Taniguchi T, Puech P, Paillet M, Michel T, Venezuela P, and Pimenta MA, Nat. Comm. 2018; 9: 1221.
Acknowledgments:PV acknowledges the support of the brazilian agencies: CNPq, Capes and Faperj.

Biography: PV earned his PhD at Universidade de So Paulo in Brazil in 1996. After that he was a pos-doc at IBM research center in Yorktown Heights, USA. Since 2002 he is a faculty at Universidade Federal Fluminense, in Niterói, Rio de Janeiro, Brazil. He has worked with electronic structure of materials and recently specially with 2D materials. In 2009/2010 he spent a sabatical year at Université Pierre at Marie Curie in Paris, where he started studying Raman spectroscopy in 2D materials in a theoretical point of view.



关于我们
下载视频观看
联系方式
通信地址

北京市海淀区清华东路甲35号(林大北路中段) 北京912信箱 (100083)

电话

010-82304210/010-82305052(传真)

E-mail

semi@semi.ac.cn

交通地图
版权所有 中国科学院半导体研究所

备案号:京ICP备05085259-1号 京公网安备110402500052 中国科学院半导体所声明