Surface optical spectroscopy of phonon and electron excitations in quasi one-dimensional metallic nanostructures

在这个项目中，我们探索的结构和电子性质的交织从光谱的原型金属纳米线在Si和Ge基板。我们将解决振动，等离子体激元和电子激发在一个广泛的光谱范围从远红外到紫外吸收/透射光谱，椭圆偏振和拉曼散射相结合。与T1密切合作，我们将促进对基本电子和声子激发方面的光学响应的微观理解，并将其与原子和电子纳米线结构以及输运性质联系起来。使用原位光谱，我们将遵循的变化与吸附物（掺杂，结构），温度和应变的控制纳米线改性，从而有助于低维金属系统的全面图片。对于准一维金属纳米线，存在竞争的电子/结构相，其稳定性可以通过掺杂、结构完整性和应变来有效地调节。我们打算解开这些参数的影响，专注于两个准一维金属系统，即Si（111）上的铟纳米线，我们的小组已经很好地建立了纯结构优化，以及邻近Si（111）以及更高折射率表面上的金纳米线，即Si（553），Si（557）和Si（775），这将在未来几年内由其他项目详细描述。除此之外，反射各向异性光谱（RAS）将继续作为一种快速，非破坏性的工具，与其他实验项目合作，精确控制表面电子结构，特别是在纳米线系统如Tb/Si（001）、Dy/Si（001）和Au/Ge（001）上。

In this project we explore the intertwinement of structural and electronic properties from optical spectroscopy of prototypical metallic nanowires on Si and Ge substrates. We will address vibrational, plasmonic, and electronic excitations in a broad spectral range from the far IR up to the UV combining absorption/transmission spectroscopy, ellipsometry and Raman scattering. In close collaboration with T1, we will promote the microscopic understanding of the optical response in terms of fundamental electronic and phononic excitations and relate that to atomic and electronic nanowire structures and to transport properties. Using in-situ optical spectroscopy we will follow the changes induced by controlled nanowire modification with adsorbates (doping, structure), temperature, and strain and will thus contribute to a comprehensive picture of low-dimensional metal systems. For quasi-1D metallic nanowires, there are competing electronic/structural phases, the stability of which can be effectively tuned by doping, structural perfection and strain. We intend to disentangle the effects from these parameters, focusing on two quasi-1D metallic systems, i.e. Indium nanowires on Si(111) for which the pure structure optimization is already well established in our group, and gold nanowires on vicinal Si(111) as well as higher index surfaces, i.e. Si(553), Si(557) and Si(775), which will be characterized in much detail by other projects during the next years.Apart from this, Reflection Anisotropy Spectroscopy (RAS) will be continuously used as a fast, non-destructive tool for precise control of the surface electronic structure in collaboration with the other experimental projects, in particular on nanowire systems such as Tb/Si(001), Dy/Si(001) and Au/Ge(001).