Synthesis and Spectroscopy of Thin Film Nickelate Superconductors

薄膜镍酸盐超导体的合成与光谱学

• 批准号: 2104427
• 负责人: Kyle Shen
• 金额: $ 43.5万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2104427&HistoricalAwards=false
• 关键词: Synthesis; Spectroscopy; Thin; Film; Nickelate

Nontechnical Abstract:The electronic properties of materials are critical to modern civilization and society, enabling technologies such as telecommunications, computing, and information storage and processing. Among these properties, superconductivity is particularly promising for applications in quantum information processing and communication, medical imaging, energy storage and transport, and electronics. The possibility to discover and engineer new superconductors with superior properties, such as higher operating temperatures or larger current densities, is one of the frontiers of modern physics. The objective of this project is to provide a more coherent and global understanding of the long-standing puzzle of high-temperature superconductivity through the investigation of a newly discovered but still enigmatic family of superconductors based on nickel oxides and comparing these materials to the closely related and more well-established family of copper oxide high-temperature superconductors. By achieving a better understanding of these nickel oxide superconductors and comparing their properties with their copper oxide cousins, this project could unlock the key ingredients for discovering higher temperature superconductors. Finally, this project provides crucial training to young scientists in materials synthesis and characterization, outreach activities, and the samples fabricated in these studies supports several scientific collaborations across the country. Technical Abstract:Layered nickelates with a Ni 1+ valence have long been proposed as close electronic analogues to the cuprates and another potential family of high temperature superconductors. The recent discovery of superconductivity at 15 K in doped rare earth nickelates in the infinite layer structure has ignited intense interest in these materials, but there are many open questions about these compounds, including the nature of the superconductivity, their underlying electronic structure, and which aspects are similar or different from the cuprates. The objectives of this project are to synthesize and investigate thin films of infinite layer nickelates using a combination of oxide molecular beam epitaxy and angle-resolved photoemission spectroscopy to address fundamental questions about the nickelates, including the momentum-dependence of the superconducting gap, the presence and nature of a pseudogap, the electronic structure of the parent compounds, and the normal state electronic structure. The research proposed here consists of two primary stages, specifically the synthesis of infinite-layer nickelate thin films, beginning with oxide MBE synthesis of precursor perovskite nickelates, followed by reduction to achieve the infinite layer structure. Next, angle-resolved photoemission spectroscopy addresses crucial questions about these nickelate superconductors, including the nature of the superconducting order parameter, the electronic structure of the parent compound, the evolution of the electronic structure with hole doping into the superconducting state, and the possible existence of a pseudogap. The samples synthesized through this project support a wide number of external collaborations, including optical spectroscopy and magnetic imaging.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.

摘要：材料的电子特性对现代文明和社会至关重要，可以实现通信、计算、信息存储和处理等技术。在这些特性中，超导性在量子信息处理和通信、医学成像、能量存储和传输以及电子学方面的应用尤其有前景。发现和设计具有更高工作温度或更大电流密度等优越性能的新型超导体的可能性是现代物理学的前沿之一。该项目的目标是通过对基于镍氧化物的新发现但仍然神秘的超导体家族的调查，并将这些材料与密切相关且更完善的氧化铜高温超导体家族进行比较，为长期存在的高温超导难题提供更连贯和全局的理解。通过更好地了解这些氧化镍超导体，并将其性能与氧化铜进行比较，该项目可以解开发现高温超导体的关键成分。最后，该项目为年轻科学家提供了材料合成和表征、推广活动等方面的重要培训，并且在这些研究中制作的样品支持了全国范围内的几项科学合作。技术摘要：具有Ni 1+价态的层状镍酸盐长期以来一直被认为是与铜酸盐和另一种潜在的高温超导体相似的电子类似物。最近在无限层结构中发现的稀土镍酸盐在15k下的超导性引起了人们对这些材料的强烈兴趣，但关于这些化合物还有许多悬而未决的问题，包括超导性的性质，其潜在的电子结构，以及哪些方面与铜酸盐相似或不同。本项目的目标是利用氧化物分子束外延和角分辨光谱学相结合的方法合成和研究无限层镍酸盐薄膜，以解决有关镍酸盐的基本问题，包括超导隙的动量依赖性、赝隙的存在和性质、母化合物的电子结构和正常状态电子结构。本文提出的研究包括两个初级阶段，即无限层镍酸盐薄膜的合成，从氧化物MBE合成前驱体钙钛矿镍酸盐开始，然后通过还原来实现无限层结构。接下来，角分辨光谱学解决了关于这些镍酸盐超导体的关键问题，包括超导序参数的性质，母体化合物的电子结构，空穴掺杂到超导状态下电子结构的演变，以及赝隙的可能存在。通过该项目合成的样品支持广泛的外部合作，包括光谱学和磁成像。该奖项反映了美国国家科学基金会的法定使命，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。

项目成果

Atomically smooth films of CsSb: A chemically robust visible light photocathode

CsSb 原子级光滑薄膜：化学稳定性强的可见光光电阴极

• DOI: 10.1063/5.0166334
• 发表时间: 2023
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: Parzyck, C. T.;Pennington, C. A.;DeBenedetti, W. J.;Balajka, J.;Echeverria, E. M.;Paik, H.;Moreschini, L.;Faeth, B. D.;Hu, C.;Nangoi, J. K.
• 通讯作者: Nangoi, J. K.

Strain-induced orbital-energy shift in antiferromagnetic RuO2 revealed by resonant elastic x-ray scattering

• DOI: 10.1103/physrevb.106.195135
• 发表时间: 2022-11-18
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Gregory，Benjamin Z.;Strempfer，Joerg;Singer，Andrej
• 通讯作者: Singer，Andrej

Magnetic excitations in the square-lattice iridate Ba2IrO4

方晶格铱酸盐 Ba2IrO4 中的磁激发

• DOI: 10.1103/physrevb.107.054423
• 发表时间: 2023
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Clancy, J. P.;Gretarsson, H.;Lupascu, A.;Sears, J. A.;Nie, Z.;Upton, M. H.;Kim, Jungho;Islam, Z.;Uchida, M.;Schlom, D. G.
• 通讯作者: Schlom, D. G.

Single-Crystal Alkali Antimonide Photocathodes: High Efficiency in the Ultrathin Limit

• DOI: 10.1103/physrevlett.128.114801
• 发表时间: 2022-03-18
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Parzyck, C. T.;Galdi, A.;Maxson, J. M.
• 通讯作者: Maxson, J. M.