Engineering and imaging enhanced spin splittings in solids

凝聚态物理学中一个重要的新兴领域是自旋电子学，它是一种利用电子自旋的电子学的变体。虽然这一概念支撑了过去20年来磁存储技术的戏剧性改进，但事实证明，自旋晶体管等有源电子设备更加难以捉摸。一个关键的挑战是创造材料底层电子态的大自旋分裂，这是将其用于在室温下运行的空间尺寸较小的自旋电子器件的先决条件。此外，这种自旋分裂必须是电可控的，才能在器件中实现开关。总而言之，这不仅将有望成为一条快速和节能的电子产品之路，而且将为实现固态量子设备中电子自旋的相干操纵开辟独特的可能性。我们将进行一系列三项互为补充的试点研究，旨在确定稳定自旋分裂的新方法，这些方法与室温相比很大，并且可以使用简单的外部控制进行调节。我们将建立一张微观图片，展示如何在有前景的硫化物和卤化物化合物中创造和操纵自旋分裂，使用先进的电子光谱直接显示它们的电子结构，并探索如何调整它，以最大限度地发挥自旋轨道耦合的影响。我们将寻求解开多个原子轨道、耦合的实自旋-轨道织构和动量-空间自旋-轨道织构以及拓扑带结构的相互关联的作用。通过这一点，我们不仅将产生新的基本理解，而且还将开发出新的组合方法，用于工程自旋分裂，其规模比迄今为止在传统基于半导体的系统中实现的要大几个数量级。该项目得到了英国和日本合作伙伴的支持，带来了材料合成和理论建模方面的互补专业知识和能力。它将利用英国独特的实验室基础设施以及关键的国家设施，将对固体自旋分裂的控制提升到新的水平，为未来的量子技术提供一种材料方法。

An important emerging field in condensed-matter physics is spintronics, a variant of electronics exploiting the electron's spin. While this concept underpins the dramatic improvements in magnetic storage technology seen over the last two decades, active electronic devices such as spin-based transistors have proved much more elusive. A key challenge is to create a large spin splitting of the underlying electronic states of materials, a pre-requisite to their use for spintronic devices operating at room temperature and having small spatial dimensions. Moreover, this spin splitting must be electrically controllable to achieve switching in a device. Together, this would not only promise a route to fast and energy-efficient electronics, but would open unique possibilities for achieving coherent manipulation of electron spins for solid-state quantum devices. We will undertake a series of three complementary pilot studies aimed at identifying new approaches to stabilise spin splittings that are large compared to room temperature and that are tuneable using simple external control. We will build up a microscopic picture of how spin splitting can be created and manipulated in promising chalcogen and halide-based compounds, using advanced electron spectroscopy to directly visualise their electronic structure and probe how it can be tuned to maximise the effects of spin-orbit coupling. We will seek to disentangle the interconnected roles of multiple atomic orbitals, coupled real and momentum-space spin-orbital textures, and topological band structure properties. Through this, we will not only generate new fundamental understanding, but also develop novel combined methodologies for engineering spin splittings orders of magnitude larger than have been achieved in conventional semiconductor-based systems to date. The project is supported by partners from the UK and Japan, brining complementary expertise and capability in materials synthesis and theoretical modeling. It will utilise unique laboratory infrastructure in the UK as well as key national facilities to advance new levels of control over spin splitting in solids, providing a materials approach to underpin future quantum technologies.