EAGER: SUPER: Coupling High-Energy Phonons into High-Tc Superconductors

EAGER：SUPER：将高能声子耦合到高温超导体中

• 批准号: 2132343
• 负责人: Yu He
• 金额: $ 30万
• 依托单位: Yale 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: 2021-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2132343&HistoricalAwards=false
• 关键词: EAGER; SUPER; Coupling; Energy; Phonons

NONTECHNICAL SUMMARYThis EAGER project supports research and education activities to create a more robust superconductor with the help from light elements on the periodic table. Superconductivity - the lossless transmission of electricity in a solid-state material - most commonly relies on the formation of electron pairs due to an attraction provided by atomic vibrations. In most bulk superconductors, this vibration is too slow to maintain the electron pairing at everyday temperatures - lots of electrons with little glue. Compounds with light elements naturally contain the fastest atomic vibrations, but the highly vibrative nature also prevents the formation of a stable, compact crystal lattice that can conduct electricity - a lot of glue with few electrons.The main goal of this EAGER project is to use advanced synthesis to create a stable and compact crystal lattice enriched with light elements such as hydrogen, carbon and lithium. This would provide both sufficient electrons and pairing glue simultaneously, therefore strengthening superconductivity to weather ambient conditions. One way is to create preferred light-element occupation sites in existing layered bulk superconductors via selected large molecule intercalation. The other is to grow high-temperature superconductors on light-element substrates layer-by-layer. Both methods are aimed to create atomic confinement of light elements in proximity to pre-existing superconducting electrons.This project supports the education of three graduate students, cohesively working across the full cycle of synthesis, characterization and theory. The intuitive and generic conceptual approach is to be developed as an important teaching example in upper division college physics curriculum. This project also offers a demonstration of the modern materials design pipeline, which will be used to develop research projects of undergraduate and public-school students.TECHNICAL SUMMARYThis EAGER project supports research and education activities that investigate the possible use of high-frequency phonons from light elements to boost superconductivity in existing high-temperature superconductors. In particular, lithium and hydrogen rich compounds will be used to boost the transition temperature and critical supercurrent of copper- and iron-based superconductors. Unlike traditional methods, which often result in uncontrolled light element placement and structural damage to the treated material, this project aims to better regulate the process with i) a dopant-assisted light-element intercalation in bulk materials, and ii) light element substrate-enhanced superconductivity in thin film superconductors. The first method creates preferred light-element occupation sites in existing layered bulk superconductors via selected large molecule intercalation. The other method aims to grow high-temperature superconductors on light-element substrates layer-by-layer. In practice, via both approaches, a highly ordered solid state structure with enriched light element composition is to be created and stabilized under ambient conditions. This project examines the effectiveness of the general framework of “hybrid” superconductivity, achieved via targeted combination of favorable superconducting contributors - strong pairing and strong conduction. The proposed bulk and thin-film synthesis complement each other in terms of tunability and applicable characterization methods. This project supports the education of three graduate students, cohesively working across the full cycle of synthesis, characterization and theory. The intuitive and generic conceptual approach is to be developed as an important teaching example in upper division college physics curriculum. This project also offers a demonstration of the modern materials design pipeline, which will be used to develop research projects of undergraduate and public-school students.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.

非技术性总结这个迫切的项目支持研究和教育活动，以利用元素周期表上的轻元素来创造更强大的超导体。超导性--固体材料中电的无损传输--最常见的依赖于电子对的形成，这是由于原子振动提供的吸引力。在大多数块状超导体中，这种振动太慢，无法在日常温度下保持电子配对--大量的电子和很少的粘合。含有轻元素的化合物自然含有最快的原子振动，但高度振动的性质也阻止了稳定、紧凑的晶格的形成，这种晶格可以导电--大量的胶水和很少的电子。这个渴望的项目的主要目标是使用先进的合成来创造一个稳定而紧凑的晶格，其中富含氢、碳和锂等轻元素。这将同时提供足够的电子和配对胶水，从而加强超导性，以适应环境条件。一种方法是通过选择大分子插层，在现有的层状大块超导体中创建首选的轻元素占位。另一种是在轻元素衬底上逐层生长高温超导体。这两种方法的目的都是在预先存在的超导电子附近建立轻元素的原子限制。该项目支持三名研究生的教育，在合成、表征和理论的整个周期内紧密合作。直观概念法应作为高师物理课程的重要教学范例加以开发。这个项目还展示了现代材料设计流水线，将用于开发本科生和公立学校学生的研究项目。技术总结这个热切的项目支持研究和教育活动，调查使用轻元素的高频声子来提高现有高温超导体的超导电性的可能性。特别是，富锂和富氢化合物将被用来提高铜和铁基超导体的转变温度和临界超流。与传统方法不同，该项目旨在通过i)掺杂辅助轻元素在块状材料中的嵌入，以及ii)轻元素衬底增强的薄膜超导体中的超导电性，来更好地调节这一过程。第一种方法通过选择大分子插层，在现有的层状大块超导体中创建优先的轻元素占位。另一种方法是在轻元素衬底上逐层生长高温超导体。在实践中，通过这两种方法，将在环境条件下产生并稳定具有丰富轻元素组合物的高度有序的固态结构。这个项目考察了“混合”超导的一般框架的有效性，通过有针对性地结合有利的超导贡献者--强配对和强传导--实现了这一点。所提出的块体和薄膜合成在可调性和适用的表征方法方面是互补的。该项目支持三名研究生的教育，在合成、表征和理论的整个周期内紧密合作。直观概念法应作为高师物理课程的重要教学范例加以开发。该项目还展示了现代材料设计流程，将用于开发本科生和公立学校学生的研究项目。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。

项目成果

High-temperature superconductivity survives

高温超导依然存在

• DOI: 10.1038/s41563-023-01552-x
• 发表时间: 2023
• 期刊: Nature Materials
• 影响因子: 41.2
• 作者: He, Yu

Role of electron-phonon coupling in excitonic insulator candidate Ta2NiSe5

• DOI: 10.1103/physrevresearch.5.043089
• 发表时间: 2023-10-26
• 期刊: PHYSICAL REVIEW RESEARCH
• 影响因子: 4.2
• 作者: Chen, Cheng;Chen, Xiang;He, Yu
• 通讯作者: He, Yu

Absence of a BCS-BEC crossover in the cuprate superconductors

• DOI: 10.1038/s41535-023-00550-1
• 发表时间: 2022-10
• 期刊: npj Quantum Materials
• 影响因子: 5.7
• 作者: J. Sous;Yu He;S. Kivelson