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Excitonic Physics of Transition Metal Dichalcogenide Monolayers and Heterostructures

过渡金属二硫族化物单层和异质结构的激子物理

基本信息

批准号：
2451533
负责人：
金额：
--
依托单位：
University of Southampton
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-2451533
关键词：
Excitonic Physics Transition Metal Dichalcogenide

项目摘要

The optical physics and applications of the transition metal dichalcogenide monolayer are dominated by excitonic and trionic states due to the confinement-enhanced coulomb interactions between electrons and holes. The strongly bound nature of these states means that large wavevector dark excitonic states are stable even at room temperature. Whilst the indirect effect of these states on luminescence and excitonic linewidths is well established the only direct probe of them currently is double resonance Raman scattering. Moire effects observed in homo and heterobilayers of these materials are another hot topic. Here Raman scattering can be used to directly probe the moire vectors and by tuning the excitation source to different electronic resonances it is possible to probe how the different excitonic states interact with the moire structure. In heterobilayers the ability to associate particular Raman peaks with phonons unique to each layer means that Raman scattering can be used to probe the hybridisation of excitons between the two layers. My project will involve the use of resonance Raman scattering and other high resolution laser spectroscopies to study the excitonic, particularly dark excitonic, physics in these extremely important materials. During the project I will study isotopically pure binary materials, quaternary alloys and the effect of strain on the bright and dark excitonic states accessible via resonance Raman scattering.

由于电子和空穴之间的束缚增强库仑相互作用，过渡金属二硫族化物单层的光学物理和应用主要是激子和三电子态。这些态的强束缚性质意味着即使在室温下，大波暗激子态也是稳定的。虽然这些状态对发光和激子线宽的间接影响已经很好地确定，但目前唯一直接探测它们的是双共振拉曼散射。在这些材料的同质层和异质层中观察到的云纹效应是另一个热点。在这里，拉曼散射可以用来直接探测云纹矢量，并且通过将激发源调谐到不同的电子共振，可以探测不同的激子态如何与云纹结构相互作用。在异质层中，将特定的拉曼峰与每层独有的声子联系起来的能力意味着拉曼散射可以用来探测两层之间激子的杂化。我的项目将涉及使用共振拉曼散射和其他高分辨率激光光谱来研究这些极其重要的材料中的激子，特别是暗激子物理。在这个项目中，我将研究同位素纯二元材料、季系合金以及应变对共振拉曼散射所能达到的明暗激子态的影响。