Emergent Unconventional Superconductivity at Interfaces between Superconductor, Topological, and Magnetic Materials

摘要：计算机无处不在，但典型的计算方法消耗巨大的能量，很快就会达到不可持续的水平。因此，一个突出的国家大挑战是开发一种更节能的方法，在不失去计算能力的情况下处理信息。该项目通过确定非常规超导材料的独特物理特性来解决这一挑战，然后可以用来设计更强大、更节能的计算机，即拓扑量子计算机。非常规超导体是一种表现出有用的零电阻状态的材料，但其性质却鲜为人知。这项工作结合了理论和实验专业知识来制造纳米级超导器件，并研究了最能建立和探测非常规超导性的材料和电子输运测量的不同组合。研究结果有助于确定在量子计算机中可能有用的特性。合作研究团队在研究活动中纳入了不同群体的本科生和研究生，并为纳米尺度和量子技术的培训提供了丰富的环境。通过课程开发、与研究相关的研讨会和特别针对物理学中代表性不足的群体的外展活动，进一步整合教育方面的内容。技术摘要：本项目的目标是确定超导体的对称性和输运性质，这些超导体由于与拓扑和铁磁材料的接近耦合而被怀疑表现出非常规的配对对称性。目的是为了更好地理解复杂的超导系统，并确定它们在电子设备中的潜在用途。实验工作包括对混合拓扑超导体/磁性结构进行相敏和量子输运测量，以确定超导秩序。实验研究与理论工作密切协调，理论工作使用数值和分析技术来分析实验数据并帮助设计新的实验。主要预期成果包括：确定接近耦合和本质超导拓扑绝缘体的配对对称性；观察是否存在外来激发，可能是马约拉纳，并确定它们与配对对称性的关系；开发探测非常规超导体的新技术，包括增强型相敏探头。合作研究团队在研究活动中纳入了不同群体的本科生和研究生，并为纳米尺度和量子技术的培训提供了丰富的环境。通过课程开发、与研究相关的研讨会和特别针对物理学中代表性不足的群体的外展活动，进一步整合教育方面的内容。

Non-Technical Abstract:Computers are ubiquitous, yet typical computation methods consume enormous amounts energy, soon to reach unsustainable levels. Thus, an eminent national grand challenge is to develop a more energy efficient method with which to process information without losing computing power. This project addresses this challenge by determining the unique physical properties of unconventional superconducting materials, which could then be used to design a more powerful and energy efficient computer, referred to as a topological quantum computer. Unconventional superconductors are materials that exhibit useful zero-resistance states, but whose properties are poorly understood. The proposed work combines theoretical and experimental expertise to fabricate nanoscale superconducting devices, and investigate the different combinations of materials and electronic transport measurements that best establish and probe unconventional superconductivity. The results of the research help determine properties that may be useful in a quantum computer. The collaborative research team incorporates a diverse group of undergraduate and graduate students in research activities and provides a rich environment for training in nanoscale and quantum technologies. Educational aspects are further integrated through course development, research-related seminars, and outreach activities that especially target groups under-represented in physics.Technical Abstract:The goal of this project is to determine the symmetry and transport properties of superconductors suspected of exhibiting unconventional pairing symmetry as result of proximity coupling to topological and ferromagnetic materials. The aim is to both better understand complex superconducting systems and also to determine their potential use in electronic devices. The experimental effort consists of making phase-sensitive as well as quantum transport measurements of the hybrid topological superconductor/magnetic structures to determine the superconducting order. The experimental research is closely coordinated with a theoretical effort that uses both numerical and analytic techniques to analyze the experimental data and aid in the design of new experiments. Key expected outcomes include: determining the pairing symmetry of proximity-coupled and intrinsically superconducting topological insulators; observing if exotic excitations, possibly Majorana, exist and determining their relation to the pairing symmetry; and developing new techniques for probing unconventional superconductors, including enhanced phase-sensitive probes. The collaborative research team incorporates a diverse group of undergraduate and graduate students in research activities and provides a rich environment for training in nanoscale and quantum technologies. Educational aspects are further integrated through course development, research-related seminars, and outreach activities that especially target groups under-represented in physics.