New Directions in Materials Characterisation Using Vortex Electron Microscopy and Spectroscopy

我将推进电子显微镜在过去十年中最深刻的发展-涡旋电子显微镜和光谱学（VEMS）的前景-研究手性和磁性器件。VEMS是一种新兴技术，它使用相位板将标准电子显微镜的平面波光束调制成螺旋波前，其涡度在显微镜探针中建立轨道角动量。与被充分研究过的光的轨道角动量状态不同，涡旋的电子电荷注入了一个可调的和量子化的磁矩，这为电子显微镜内的衍射和光谱提供了一个完全未开发的自由度。到目前为止，国际上的研究主要集中在自由电子涡旋束的产生上。我的目标是探索这些光束与我在研究期间开发的样品的相互作用。VEMS之所以令人感兴趣，主要是因为新的磁性自由度可能赋予磁性和手性介质在散射和衍射方面的敏感性，从而能够研究以前只有在国际x射线或中子设施才能获得的材料特性。例如，VEMS可以对氧化物界面的磁性和电荷顺序产生前所未有的见解，并在这些技术相关材料的表征方面赋予真正的世界领先地位。此外，我将探索将VEMS应用于等离子体超材料研究的新方向-包括生物传感和电磁伪装在内的广泛应用的器件。预计VEMS探针的螺旋性质将与超材料内部建立的手性电场强烈耦合，从而产生独特的、空间分辨的表征工具，将为超材料设计提供新的见解。该项目具有三重前景：提供新的研究途径，提高我的国际声誉，并大大加强我们对我的奖学金中已经探索的材料的理解。它充分利用格拉斯哥大学在基础设施和专业知识方面的显著优势，并将创造新的合作机会。

I will advance the most profound development in electron microscopy in the past decade - the prospect of vortex electron microscopy and spectroscopy (VEMS) - to study chiral and magnetic devices. VEMS is a nascent technique that uses phase-plates to modulate the plane-wave beam of a standard electron microscope into a helical wavefront, the vorticity of which establishes orbital angular momentum in the microscope's probe. Unlike the well-studied orbital angular momentum states of light - the vortex's electronic charge imbues a tunable and quantised magnetic moment that provides a completely unexplored degree of freedom for diffraction and spectroscopy within the electron microscope. Thus far, international research has focused on the production of free electron vortex beams. My aim is to explore the interaction of these beams with samples developed during my fellowship. VEMS is intriguing principally because the new magnetic degree of freedom may impart sensitivity to magnetic and chiral media in scattering and diffraction, thereby enabling the study of material properties that have previously only been accessible at international x-ray or neutron facilities. For example, VEMS could yield unprecedented insight into magnetic and charge ordering at oxide interfaces and confer a genuine world lead in the characterisation of these technologically-relevant materials. In addition, I will explore the new direction of applying VEMS to the study of plasmonic metamaterials - devices with wide-ranging applications including bio-sensing and electromagnetic camouflage. The helical nature of the VEMS probe is expected to couple strongly to chiral electric fields established within metamaterials, producing a unique, spatially resolved characterisation tool that will yield new insights into metamaterial design. The project has the triple prospects of providing a new avenue of research, improving my international reputation and substantially enhancing our understanding of the materials already being explored in my fellowship. It capitalises on notable advantages in infrastructure and expertise at the University of Glasgow and will build new collaborative opportunities.