Magnetic topological insulators for robust Majorana bound states

我们建议研究磁性、能带拓扑和超导电性之间的相互作用，目的是实现健壮的拓扑态，作为未来量子计算的基石。我们的项目将结合实验、材料模拟和固态理论来研究基于具有邻近感应超导电性的磁性拓扑绝缘体(MTI)的Majorana束缚态。该联盟提供的独特的实验平台及其理论知识非常适合解决这一挑战。在实验方面，我们将以不同的几何形状原位构建MTI纳米结构，例如纳米线、结或干涉仪。磁输运测量将使我们能够详细地表征器件及其在正常导电状态下的拓扑性质。接下来，我们将使用超导引线来研究邻近感应超导电性和基于MTI的约瑟夫森结。这最终将使基于MTI创建和检测Majorana绑定状态成为可能。我们的理论和模拟集群使用的技术将允许对基于纳米结构的设备进行多尺度建模，并将密切伴随着实验工作。实验和理论之间不断的反馈循环将帮助我们优化器件的几何形状和材料。虽然大量的MTI已经被详细研究，但它们的纳米结构仍然留下了许多基本的问题。因此，该项目将在理论和实验上对MTIs产生重要的新见解。后者反过来将引导我们达到我们项目的最终目标，那就是明确地识别MTI纳米线中的Majorana束缚态，并为它们未来在拓扑量子计算中的应用铺平道路。

We propose to study the interplay between magnetism, band topology, and superconductivity with the aim of realizing robust topological states as future building blocks for quantum computation. Our project will combine experiments, materials simulations, and solid-state theory in order to study Majorana bound states based on magnetic topological insulators (MTIs) with proximity-induced superconductivity. The unique experimental platform available within this consortium as well as its theoretical know-how are ideally suited to address this challenge. On the experimental side, we will construct MTI nanostructures in situ in different geometries, e.g., as nanowires, junctions, or interferometers. Magnetotransport measurements will allow us a detailed characterization of the devices and their topological properties in the normal-conducting state. Next, we will apply superconducting leads for studying proximity-induced superconductivity and Josephson junctions based on MTIs. This finally will make it possible to create and detect Majorana bound states based on MTIs. The techniques used by our theory and simulation cluster will allow multiscale modelling of nanostructure-based devices and will closely accompany the experimental efforts. A constant feedback loop between experiments and theory will help us optimize device geometries and materials. While bulk MTIs have been investigated in detail, their nanostructures still leave open many fundamental questions. This project will therefore lead to important new insights, both in theory and experiment, about MTIs. The latter, in turn, will lead us to the ultimate goal of our project, which is to unambiguously identify Majorana bound states in MTI nanowires, and to pave the way for their future use in topological quantum computation.