International network to explore novel superconductivity at advanced oxide superconductor/magnet interfaces and in nanodevices

国际网络探索先进氧化物超导体/磁体界面和纳米器件的新型超导性

• 批准号: EP/P026311/1
• 负责人: Jason Robinson
• 金额: $ 87.22万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP026311%2F1
• 关键词: International; network; explore; novel; superconductivity

This International Network of world-leading experimental and theoretical groups in Japan, South Korea, Italy and the UK will lead a programme to explore novel superconductivity at oxide superconductor interfaces with magnetic materials and in nanodevices. Through a better understanding of materials properties and processing, our vision is to realise full control over superconducting symmetry at oxide interfaces and to setup Cambridge and Kyoto as a global hubs to explore the science of advanced oxide interfaces and unconventional superconductivity. The past decade has seen rapid developments in the understanding of unconventional superconductivity at the interface between conventional (s-wave) superconductors and ferromagnets [Nature Physics 11, 307 (2015)]. A highlight was the experimental demonstration of a triplet proximity effect by the UK applicants [Science 329, 59 (2010)], which required the transformation of spin-singlet Cooper pairs by a spin-mixing interface into spin-triplet pairs. Another example is a possible creation of electron-composite particle-antiparticles in nanowire/superconductor devices. Such Majorana Fermions are also expected in a half-quantum flux state of a spin-triplet superconductor, and the Japanese core member (Maeno) obtained the first evidence for this using superconducting micro-rings [Science 311, 186 (2011)]. In parallel, the understanding of unconventional superconductivity in superfluid helium and in compounds such as Sr2RuO4 (SRO) [e.g. Science 331, 186-188 (2011) and Science 344, 283 (2014)] has also seen dramatic advances. The triplet (p-wave) state in SRO is even-frequency and is conceptually different to the odd-frequency triplet pairing induced in ferromagnets on s-wave superconductors. However, there are theoretical predictions that alternative pairing states can be induced at surfaces, which raise the prospect of coupling different superconducting states via interface-engineered proximity effects between SRO and conventional superconductors. One of the key aims of the Network is to investigate the coupling of different superconducting symmetries taking SRO and ferromagnet/superconductor structures as a model system. There are theoretical predictions that the surface of SRO and ferromagnet/superconductor hybrids can support an induced odd-frequency triplet-state and so there should be a proximity effect from the conventional superconductor which would create or enhance the superconductivity in a SRO crystal or thin-film. Achieving this will enable detailed studies of the electron pairing state in SRO and the mixing of different superconducting order parameters, which have not previously been possible with single crystal samples.To bridge these novel superconducting states at oxide interfaces, further materials developments are critical. The global interest in unconventional superconductivity and recent high-impact realisations could lead to transformative science and simultaneously offer new paradigms of cryogenic computing and encryption. To lead this research, the Cambridge and Kyoto hubs will bring together different specialities including superconductivity, thin-film and crystal growth of oxides, materials characterization (XMCD, low energy muon spectroscopy, pump-probe terahertz spectroscopy, angle-resolved photoemission, electron microscopy), nanofabrication and theory. The members of the Network will work closely together with PhD students, PDRAs and investigators undertaking routine research visits between the member groups. As importantly the Network will actively engage with the wider scientific community through the organisation of conferences and student workshops, and research visits with the overarching aim of triggering a long-term global effort to lift basic science to application.

这个由日本、韩国、意大利和英国世界领先的实验和理论小组组成的国际网络将领导一个项目，探索氧化物超导体与磁性材料和纳米器件界面的新型超导性。通过更好地了解材料特性和加工，我们的愿景是实现对氧化物界面超导对称性的完全控制，并将剑桥和京都建立为探索先进氧化物界面和非常规超导科学的全球中心。过去十年，人们对传统（s 波）超导体和铁磁体之间界面的非常规超导性的理解取得了快速发展 [Nature Chemistry 11, 307 (2015)]。一个亮点是英国申请人对三重态邻近效应的实验演示[Science 329, 59 (2010)]，该实验需要通过自旋混合界面将自旋单重态库珀对转化为自旋三重态对。另一个例子是在纳米线/超导体器件中可能产生电子复合粒子-反粒子。这种马约拉纳费米子也有望出现在自旋三重态超导体的半量子通量态中，日本核心成员（Maeno）利用超导微环获得了第一个证据[Science 311, 186 (2011)]。与此同时，对超流氦和 Sr2RuO4 (SRO) 等化合物中非常规超导性的理解 [例如Science 331, 186-188 (2011) 和 Science 344, 283 (2014)] 也取得了巨大的进展。 SRO 中的三重态（p 波）态是偶数频率，在概念上不同于 s 波超导体上的铁磁体中感应的奇数频率三重态配对。然而，有理论预测，可以在表面诱导替代配对态，这提高了通过 SRO 和传统超导体之间的界面设计邻近效应耦合不同超导态的前景。该网络的主要目标之一是以 SRO 和铁磁体/超导体结构作为模型系统来研究不同超导对称性的耦合。有理论预测，SRO 和铁磁体/超导体混合体的表面可以支持感应奇数频率三重态，因此应该存在来自传统超导体的邻近效应，这将在 SRO 晶体或薄层中产生或增强超导性。电影。实现这一目标将能够详细研究 SRO 中的电子配对状态以及不同超导序参数的混合，这在以前的单晶样品中是不可能实现的。为了在氧化物界面上桥接这些新颖的超导状态，进一步的材料开发至关重要。全球对非常规超导性的兴趣和最近的高影响力实现可能会带来变革性的科学，同时提供低温计算和加密的新范例。为了领导这项研究，剑桥和京都中心将汇集不同的专业，包括超导性、氧化物薄膜和晶体生长、材料表征（XMCD、低能μ子光谱、泵浦探针太赫兹光谱、角分辨光电发射、电子显微镜） ）、纳米制造和理论。该网络的成员将与博士生、PDRA 和研究人员密切合作，在成员团体之间进行例行研究访问。同样重要的是，该网络将通过组织会议、学生研讨会和研究访问，积极与更广泛的科学界接触，其总体目标是引发全球长期努力，将基础科学提升到应用。

项目成果

A Review of Electronic Transport in Superconducting Sr2RuO4 Junctions

超导Sr2RuO4结中电子输运的研究进展

• DOI: http://dx.10.3390/coatings11091110
• 发表时间: 2021
• 期刊: Coatings
• 影响因子: 3.4
• 作者: Anwar M

Colloquium: Spin-orbit effects in superconducting hybrid structures

研讨会：超导混合结构中的自旋轨道效应

• DOI: http://dx.10.48550/arxiv.2210.03549
• 发表时间: 2022
• 作者: Amundsen M

Radio-Frequency Capacitive Gate-Based Sensing

基于射频电容门的传感

• DOI: http://dx.10.1103/physrevapplied.10.014018
• 发表时间: 2018
• 期刊: Physical Review Applied
• 影响因子: 4.6
• 作者: Ahmed I

Magnetic field tunable superconducting transition in Nb/Co/Py/Nb exchange spring multilayers

Nb/Co/Py/Nb 交换弹簧多层中的磁场可调谐超导转变

• DOI: http://dx.10.1063/1.5139266
• 发表时间: 2020
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Bhatia E

A Review of Electronic Transport in Superconducting Sr$_2$RuO$_4$ Junctions

超导 Sr$_2$RuO$_4$ 结中电子输运综述

• DOI: http://dx.10.48550/arxiv.2109.05851
• 发表时间: 2021
• 作者: Anwar M