EAGER: Resolving the issue of pairing symmetry in Sr2RuO4

非技术描述：超导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。走向量子计算的努力要求对超导的基本物理有更深的理解。例如，可以用奇异的自旋三重态超导体实现容错拓扑量子计算。直到2019年，单层Ruthenate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，支持这一说法的其中一个实验是不正确的。这导致了关于这种材料超导性质的争论。这一实验和理论项目将致力于解决这一争议，并在STEM培养来自少数族裔社区的未来科学家，以帮助满足新兴量子技术对人力资源的需求。技术描述：由轨道和自旋部分组成的超导序参数的对称性是超导研究的基本兴趣。直到2019年，单层Ruthenate锶(SRO)一直被认为是自旋三重态超导电性的主要候选者，因为1998年一项重要的核磁共振奈特移位实验的结果被证明是不正确的，该实验探测了有序参数的自旋部分。这导致一些研究人员提出，SRO实际上是一个自旋单态。另一方面，基于约瑟夫森效应的SRO相敏实验表明，SRO中序参数的轨道部分具有奇宇称，这意味着由于这种材料中存在反转对称性，SRO是一个自旋三重态。关于SRO中配对对称性的激烈辩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中奇数等序参数的确定，并确定将其与探索自由的自旋程度的工作相协调的方法。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.