Spectroscopic Detection of Magnetic Scattering and Quasiparticles at Atomic Resolution in the Electron Microscope

半导体器件已经彻底改变了科学和技术，其基础是控制纳米尺度材料中电子电荷传输的能力。然而，作为逻辑器件构建模块的晶体管的集成化正在达到瓶颈，电荷传输的速度正在达到其物理极限，这凸显了对新器件设计的需求。电子设备中使用的电子携带一条额外的信息，称为自旋。所谓的自旋电子器件除了利用电子的电荷外，还利用电子的自旋来更快更有效地传输信息。因此，它们有可能克服传统电子产品的局限性。实现这一概念的一种方法是通过在自旋电子材料中产生“信息波”，即电荷载流子自旋的周期性振荡，其在器件内传播。这些自旋波也被称为“磁振子”。为了在新的电子产品中有效地使用这些磁振子，有必要可视化和理解它们是如何在自旋电子器件中跨界面或接触产生和传输的，从而阐明如何有效地携带信息。到目前为止，还没有实验工具或方法可以在相关的纳米甚至原子尺度上提供这些信息。在过去的十年中，电子显微镜领域的时代定义技术和方法的发展已经看到了当前一代仪器的能量分辨率达到了低于5 meV的水平，同时保持原子尺度的空间分辨率。这种突破性的能力，应该能够检测所引起的能量损失的电子探针分散在样品中被观察时，激发磁振子，这是在这个meV的能量范围。因此，这个国际中心到中心的合作项目汇集了一个团队，其研究和专业知识处于扫描透射电子显微镜（STEM）和电子能量损失谱（EELS）的最前沿，在先进电子显微镜和电子散射建模领域产生知识，工具和方法方面拥有丰富的经验，该项目旨在开发实验和理论工具，使我们能够利用电子光谱学在纳米和原子尺度上检测和可视化磁振子。一个主要的目标是明确的指纹磁振子的自旋电子应用的材料中的光谱特征，并将这种观察与分析电子显微镜可以提供的丰富的结构和化学信息。最先进的计算工具将使我们能够指导和设计实验参数，并合理化实验结果。该项目将提供一种新的方法来研究固态中的磁有序和自旋波激发的基本原理，并将提供材料和器件的磁性和电子特性的完整图像。

Semiconductor devices that have revolutionised science and technology are based on the ability to control the transport of electron charges in nanoscale-sized materials. However, the miniaturisation of transistors, the building blocks of logic devices, is reaching a bottleneck and the speed of charge transport is reaching its physical limits, highlighting the need for new device designs. Electrons being used in electronic devices carry an additional piece of information called spin. So-called spintronic devices exploit this electron spin, in addition to its charge, to transport information more quickly and effectively. As a result, they have the potential to overcome the limitations of conventional electronics. A way to implement this concept is through the creation in spintronic materials of 'information waves', periodic oscillations of the spin of charge carriers, which propagate within the devices. These spin waves are also called 'magnons'. In order to effectively use these magnons in new electronics, it is essential to visualise and understand how they are generated and transferred within spintronic devices across interfaces or contacts and thus shed light on how effectively information can be carried. Up to now, no experimental tool or method has been available to provide this information at the relevant nano- or even atomic scale.Era-defining technological and methodological developments in the last decade in the field of electron microscopy have seen the energy resolution of current-generation instruments reach the sub-5meV level while retaining atomic-scale spatial resolution. Such ground-breaking capabilities should enable the detection of energy losses incurred by electron probes scattered within samples being observed when exciting magnons, which lie in this meV energy range. This International Centre-to-Centre Collaborative project thus assembles a team whose research and expertise are at the forefront of scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS), with extensive experience in generating knowledge, tools, and methodologies in the fields of advanced electron microscopy and modelling of electron scattering, with a view to demonstrate magnon EEL spectroscopy in the electron microscope.The project aims to develop the experimental and theoretical tools that will allow us to detect and visualise magnons at the nano and atomic scale with electron-based spectroscopy. A main goal is to fingerprint unambiguously the spectroscopic signature of magnons in materials for spintronic applications and to correlate this observation with the wealth of structural and chemical information that analytical electron microscopy can provide. State-of-the-art computational tools will allow us to guide and design experimental parameters and to rationalised experimental results. This project will provide a new way of studying the fundamentals of magnetic ordering and spin wave excitations in the solid state and it will provide a complete picture of magnetic and electronic properties of materials and devices.