EAGER: Resolving the issue of pairing symmetry in Sr2RuO4

EAGER：解决 Sr2RuO4 中的配对对称性问题

• 批准号: 2312899
• 负责人: Ying Liu
• 金额: $ 25.32万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-15 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2312899&HistoricalAwards=false
• 关键词: EAGER; Resolving; issue; pairing; symmetry

Non-technical description:Superconductivity is a macroscopic quantum phenomenon highly relevant to quantum computing and other quantum technologies. The drive towards quantum computing calls for deeper understanding of the fundamental physics of superconductivity. For example, the implementation of fault tolerant topological quantum computing may be achievable with exotic spin-triplet superconductors. Single-layer strontium ruthenate (SRO) had been a leading candidate for a spin-triplet superconductor up to 2019. However, it turned out that one of the experiments that supported that claim in SRO is incorrect. This led to a controversy on the nature of superconductivity in this material. This experimental and theoretical project will aim to address this controversy as well as train future scientists from underrepresented minority communities in STEM to help meet the human resource needs of emerging quantum technologies.Technical description:The symmetry properties of the superconducting order parameter, which consists of orbital and spin parts, are of fundamental interest for superconductivity research. Single-layer strontium ruthenate (SRO) was considered a leading candidate for spin-triplet superconductivity up to 2019 when results from an important NMR Knight shift experiment from 1998, which probes the spin part of the order parameter, was shown to be incorrect. This led to suggestions by some researchers that SRO is actually a spin singlet. On the other hand, the Josephson effect based phase-sensitive experiments on SRO, which have remained largely unchallenged, suggest that the orbital part of the order parameter in SRO is of an odd parity, which implies that SRO is a spin triplet due to the presence of an inversion symmetry in this material. The heated debate on the pairing symmetry in SRO calls for new theoretical insights and additional experimental inputs. This project aims to strengthen the previous determination of the odd parity order parameter in SRO as well as identify ways to reconcile this with work probing the spin degrees of freedom.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：超导性是一种与量子计算和其他量子技术高度相关的宏观量子现象。量子计算的发展需要对超导的基本物理学有更深入的理解。例如，容错拓扑量子计算的实现可以用奇异自旋三重态超导体来实现。到2019年，单层的三烯酸锶（SRO）一直是自旋三重态超导体的主要候选者。然而，事实证明，SRO中支持这一说法的实验之一是不正确的。这导致了关于这种材料的超导性的争论。该实验和理论项目旨在解决这一争议，并培养未来科学家，以帮助满足新兴量子技术的人力资源需求。技术描述：超导序参量的对称性，其中包括轨道和自旋部分，是超导研究的基本兴趣。在2019年之前，单层铼酸锶被认为是自旋三重态超导性的主要候选者，但1998年的一项重要NMR奈特位移实验的结果被证明是不正确的，该实验探测了序参量的自旋部分。这导致一些研究人员认为SRO实际上是自旋单线态。另一方面，基于约瑟夫森效应的SRO相敏实验，这在很大程度上仍然没有受到挑战，表明SRO中的序参数的轨道部分是奇宇称，这意味着SRO是一个自旋三重态，由于在这种材料中存在反转对称性。SRO中对对称性的激烈争论需要新的理论见解和额外的实验投入。该项目旨在加强先前对SRO中奇宇称序参数的测定，并确定如何将其与探测自旋自由度的工作相协调。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。