Tailoring and Exploring Rare-Earth-Sulfides thin films with enhanced Magneto-Optical properties (TERESMO)

纳米技术的最新技术创新主要是基于材料性能的调整。纳米级工程材料是学术界和工业界最感兴趣的领域。在纳米尺度上理解和控制材料特性会导致新的尚未探索的现象。随着2D硫化物等新材料的出现，人们越来越有兴趣研究它们的基本性质，并将其用于未来的应用。在硫化物中，稀土硫化物（RES）是令人瞩目的兴趣，他们几乎没有从基础和应用的角度进行研究。一个迷人的话题是快速磁光应用的磁状态的光学控制，然而，它们各自的属性在很大程度上是未开发的。到目前为止，RES材料没有表现出与其他氧化物或其他金属硫化物相同的成熟度。最重要的是，没有可靠的合成配方来大规模种植这些高质量的材料。虽然化学气相沉积（CVD）和原子层沉积（ALD）在制备金属硫化物方面获得了很多关注，但由于缺乏合适的RE前驱体，RES薄膜的合成受到限制。因此，该项目的目标是为EuS，Nd 2S 3，Er 2S 3和SmS开发新的CVD和ALD工艺，采用新的前体，并阐述其磁光弹性特征，包括具有巨磁矩的集体铁磁态（CFS）的光学创建。与稀土前体，这是目前的限制，在其物理化学性质的缺点将得到解决和改进的配体设计的合理方法。然后将彻底研究CVD和ALD生长的RES层的晶体结构、成分和形态。层厚度将缩小到纳米，最终达到2D RES薄膜。层的厚度变化以及前体的类型是固定螺钉的RES的磁光和磁弹性特性。在这方面，共振激光光谱将揭示其辐射和非辐射带间跃迁，其耦合到外部磁场和晶格以及磁振子-声子相互作用。CFS的光产生将进一步研究依赖于RES薄膜的晶体学和磁性结构以及特定的共振激光激发。时间分辨的CFS的形成和稳定性的最后解决的泵和探针法拉第旋转实验。新开发的具有定制功能特性的RES薄膜与先进的共振光谱相结合，将为RES薄膜在光电子和磁光应用中的潜力提供全面的见解。

The recent technical innovations in nanotechnology are mainly based on tuning the material properties. Engineering materials at the nanoscale is of utmost interest both for academic and industrial sectors. Understanding and controlling the material features at the nanometer scale lead to new and yet unexplored phenomena. With the emergence of new materials, such as 2D sulfides, there is growing interest to study their fundamental properties with the vision of employing them for future applications. Among the sulfides, the rare earth sulfides (RES) are of remarkable interest; they have barely been studied from the fundamental as well as application point of view. A fascinating topic is the optical control of their magnetic state for fast magneto-optical applications; however, their respective properties are largely unexplored. Up to now, the RES materials do not exhibit the same degree of maturity like other oxides or other metal sulfides. Most importantly there is no reliable synthetic recipe to grow these materials of high quality on a large scale. Although chemical-vapor deposition (CVD) and atomic-layer deposition (ALD) gain a lot of attention for processing metal sulfides, the synthetization of RES films is limited due to the lack of suitable RE precursors. This project will thus aim both at developing new CVD and ALD processes for EuS, Nd2S3, Er2S3, and SmS employing new precursors as well as at elaborating their magneto-opto-elastic features including the optical creation of collective ferromagnetic states (CFS) with giant magnetic moments. The drawbacks associated with RE precursors which are as-of-now limited in their physico-chemical properties will be addressed and improved by a rational approach on the ligand design. The CVD and ALD grown RES layers will then thoroughly be investigated on their crystallographic structure, composition and morphology. The layer thickness will be scaled down to nanometers, ultimately reaching 2D RES films. The layer thickness variation as well as the type of precursor are setscrews for the magneto-optical and magneto-elastic characteristics of the RES. In this respect, resonant laser spectroscopy will reveal their radiative and non-radiative interband transitions, their coupling to an external magnetic field and to the lattice as well as magnon-phonon interactions. The optical generation of CFS will further be studied in dependence on the crystallographic and magnetic structure of the RES thin films as well as on specific resonant laser excitations. The time-resolved formation and stability of the CFS are finally addressed by pump&probe Faraday rotation experiments. The newly developed RES films with tailored functional properties combined with the advanced resonant spectroscopy will provide a comprehensive insight into the potential of RES films for opto-electronic and magneto-optical applications.