Development of a high-energy-, high-spatial-, and high-momentum-resolution electron energy loss spectrometer with liquid-Helium cooling stage (HR3-EEL spectrometer)

开发具有液氦冷却级的高能、高空间、高动量分辨率电子能量损失谱仪（HR3-EEL谱仪）

• 批准号: 461150024
• 负责人: Dr. Thomas Gemming
• 金额: --
• 依托单位: Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (IFW) e.V.
• 依托单位国家: 德国
• 项目类别: New Instrumentation for Research
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/461150024?language=en
• 关键词: Development; energy; spatial; momentum; resolution

The last two decades have witnessed substantial development of spectroscopy techniques that probe low-energy excitations in solids, which, in many cases, lead to important breakthroughs in the understanding of fundamental solid-state effects. Prominent examples are Angular Resolved Photoemission Spectroscopy (ARPES) or Scanning Tunneling Spectroscopy (STS), which, amongst others, demonstrated the existence of gapless surface states in topological insulators and anisotropic gaps in high-temperature superconductors. That was possible because these techniques probe excitations at the surface with an excellent energy resolution (meV regime and below depending on cryogenic conditions) and high spatial or angular resolution. Nevertheless, a spectroscopic technique for analyzing electronic and vibrational excitations in the bulk (and surface) with simultaneous high-energy, high-momentum, and high-spatial resolution down to deep cryogenic conditions (liquid Helium cooling) is still missing. Such a tool would, for instance, allow studying the diverse class of low-dimensional structures (e.g., interfaces, van der Waals materials) with high momentum resolution in the extended dimensions, while maintaining high-spatial resolution in the inhomogeneous direction. It would allow deliberately tailoring spatial and momentum resolution for investigating the details of the dielectric response in complex nanostructures (e.g. nanophotonic and electronic devices, organic semiconductors, but also defects) including non-local dielectric response effects such as spatial variations in the dielectric dispersion. It is the aim of this project to realize this ambition by building a comprehensively improved Transmission Electron Energy Loss spectrometer. Crucial ingredients are a newly developed magnetic ground potential monochromator, a new continuous flow L-He sample stage, an improved sector magnet energy filter, and fast 2D CMOS electron detectors, which are integrated into an adapted state-of-the-art TEM platform including a cold field emission gun and a comprehensive, freely configurable condenser and projection optics, amongst others. The instrument will reach sub 10 meV energy resolution, few nm spatial resolution, sub 1/µm momentum resolution, and sub 10 K temperature in parallel in EEL spectroscopy mode as well as atomic resolution, electric and magnetic field sensing in other operation modes. This breakthrough in various key figures allows drastically widen our basic understanding of the charge density response function in various topical materials such as high-Tc superconductors, topological insulators, Weyl and Dirac semimetals, plasmonic nanostructures, organic semiconductors, soft biologic matter, or correlated matter, providing insight into their specific and universal ground state and dynamic properties (e.g., charge transport, dielectric response, electronic and phononic band structure, charge ordering).

在过去的二十年中，探测固体中低能兴奋的光谱技术的实质性发展，在许多情况下，这在理解基本固态效应方面带来了重要的突破。突出的例子是角度分辨的光发射光谱法（ARPE）或扫描隧道光谱法（STS），其中包括在拓扑绝缘子中存在无间隙表面状态和高温超导体中的各向异性差距。之所以可以，是因为这些技术在表面上具有出色的能量分辨率（MEV状态及以下取决于低温条件）和高空间或角度分辨率。然而，一种用于在散装（和表面）中分析的电子和振动兴奋的光谱技术，具有简单的高能量，高弹药和高空间分辨率，直至深度低温条件（液体氦气冷却）。例如，这种工具将允许研究潜水员类别的低维结构（例如接口，范德华材料），并在扩展尺寸中具有高动量分辨率，同时在不均匀方向上保持高间隙分辨率。它将故意调整空间和动量解决方案，以研究复杂纳米结构中的饮食反应细节（例如，纳米光和电子设备，有机半导体，以及缺陷），包括非本地饮食反应，例如饮食分散体中的空间变化等非本地饮食反应效应。该项目的目的是通过全面改进的传输电子损耗光谱仪来实现这一野心。至关重要的燃料是新开发的磁化地面电势单色器，一个新的连续流量L-HE样品阶段，改进的扇形磁铁能量滤波器和快速的2D CMOS电子探测器，它们被整合到适应的最先进的TEM平台中，包括一个冷场排放枪和一个全面的可构造式凝聚器和可配置的冷凝器和投影选择。该仪器将达到10 MEV能量分辨率，NM空间分辨率很少，次1/µM动量分辨率和EEL光谱模式下平行的10 K温度以及其他操作模式下的原子分辨率，电气和磁场灵敏度。在各种关键数字中的这一突破使我们对电荷密度响应函数的基本理解在各种局部材料中的基本了解，例如高-TC超导体，拓扑绝缘子，Weyl和Dirac半学，等离激元纳米结构，有机半导体，有机半导体，软生物学物质或相关性和响应式和通用的属性和动态性属性和动态性的（动态式），并提供了动态的构成（可启用），并提供动态的动态。声音带结构，充电排序）。