Spectroscopic Studies on Layered Materials

本项目由材料研究部（DMR）的电子与光子材料计划（EPM）和凝聚态物理计划（CMP）支持。非技术描述：本研究项目旨在显著扩展纳米科学研究领域的重要课题的知识，包括纳米碳材料，过渡金属二硫族化合物的超薄层形式，厚度只有几个原子层，以及新发现的磷材料称为磷烯，它具有新颖的层状晶体结构和有前途的电子，光学和光谱性质。研究成果发表在主要科学期刊上，并由主要研究人员和参与研究的学生及博士后在国内和国际科学会议上发表，为他们提供了宝贵的教育经验。此外，首席研究员在大学举办学术讨论会，并在科学会议上邀请演讲，进一步推动纳米科学研究领域。技术描述：该项目是对纳米碳、石墨烯、过渡金属二硫族化合物和磷烯的综合比较研究。拉曼光谱是主要的实验方法。石墨烯的研究利用现有的庞大的石墨烯电子性质知识库来研究拉曼共振窗口、扭角现象和电子-声子相互作用现象的新方面。这些研究也可以最好地在石墨烯中进行，因为它的特殊性质，如碳12和碳13同位素提供的大同位素效应，这有利于定量研究电子-声子相互作用。同样，衬底效应在增强拉曼光谱信号和由外部扰动产生的对称性破坏现象中的作用已经在石墨烯中得到了广泛的研究，现在可以用于计量目的。在这种情况下，类似的物理性质现在可以在少数层过渡金属二硫族化合物和磷烯单独和比较的基础上进行富有成效的研究。

This project is supported by the Electronic and Photonic Materials Program (EPM) and Condensed Matter Physics Program (CMP), both in the Division of Materials Research (DMR).Nontechnical Description: This research project aims to significantly expand the knowledge on important topics in a nanoscience research field, including nanocarbon materials, transition-metal dichalcogenides in the form of ultrathin layers with thicknesses of only a few atomic layers, and the newly discovered few-layered phosphorus material called phosphorene, which has a novel layered crystal structure and promising electronic, optical, and spectroscopic properties. The research results are published in major scientific journals and presented at national and interternatinal scientific conferences by the principal investigator and participating students and postdoctoral researchers, thereby providing valuable educational experiences for them. In addition, the principal investigator gives colloquia at universities and invited talks in scientific conferences, furthering the nanoscience research field.Technical Description: The project is on a comprehensive and comparative study of nanocarbons, graphene, transition metal dichalcogenides, and phosphorene. Raman spectroscopy is the main experimental method. The graphene research studies take advantage of the large present knowledge base of the electronic properties of graphene to study new aspects of Raman resonance windows, twist angle phenomena, and electron-phonon interaction phenomena. These studies also can be best carried out in graphene because of its special properties, such as the large isotope effect provided by the carbon 12 and 13 isotopes, which is advantageous for studying electron-phonon interactions quantitatively. Similarly, the role of substrate effects in enhancing Raman spectroscopy signals and symmetry-breaking phenomena produced by external perturbations have been extensively studied in graphene, which now can be used for metrological purposes. In this context, similar physical properties can now be studied productively in few-layer transition metal dichalcogenides and phosphorene individually and on a comparative basis.