THz and subTHz Excitations in Graphene Based Materials:Magneto-Optical Studies

本项目旨在通过不同的方法，如外延生长、化学气相沉积、石墨烯剥离或从块体石墨中分离石墨烯来详细了解石墨烯材料的低能电子结构。这将通过在太赫兹和亚太赫兹区域分别使用红外和高频电子顺磁共振光谱仪在频率和磁场领域进行磁光研究来完成。我们建议首次对石墨烯样品进行系统的比较研究，这些样品因衬底、缺陷、尺寸和晶界等而不同。非侵入性的低能量(0.4-40 meV)实验方法将带来关于本征电荷迁移率极限、电子能带结构(费米面)和其他现象的决定性信息，如受限等离子体、磁激发等。低能激发将被跟踪作为层数的函数，以映射和了解从单层到块体石墨的电子性质的变化。我们还将首次在门控石墨烯薄片中进行微波磁吸收测量，目的是控制受限等离子体频率。这将是迈向光电子器件的第一步。

This project aims to achieve a detailed understanding of the low-energy electronic structure of graphene based materials prepared by different methods such as epitaxial growth, CVD, exfoliation or decoupled graphene from bulk graphite. This will be done by magneto-optical studies in the THz- and sub-THz region using infrared and high frequency electron paramagnetic resonance spectrometers, respectively, both in frequency and magnetic field domains. We propose the first systematic comparative study of graphene specimens, which differ by substrate, defects, size and grain boundaries etc. Noninvasive low-energy (0.4-40 meV) experimental methods will bring decisive information about limits of intrinsic charge mobility, the electronic band structure (Fermi surface) and other phenomena, like confined plasmons, magnetic excitations etc. The low-energy excitations will be followed as a function of numbers of layers, to map and understand the change in electronic properties going from monolayer to bulk graphite. We will also perform the first microwave magneto-absorption measurements in gated graphene flakes with the aim to control confined plasmon frequency. This will be the first step towards optoelectronic devices.