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New Probes of Strong Interactions in Quantum Matter

量子物质强相互作用的新探针

基本信息

批准号：
1919143
负责人：
Philip Phillips
金额：
$ 16.5万
依托单位：
University of Illinois at Urbana-Champaign
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-10-01 至 2022-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1919143&HistoricalAwards=false
关键词：
New Probes Strong Interactions Quantum

项目摘要

NONTECHNICAL SUMMARYEliminating inefficiencies in electrical conduction in the power grid by the use of superconducting wires could result in the saving of billions of dollars. The AmpaCity project in Essen Germany is one such example. However, a major obstacle to achieving that goal is understanding how to design new superconductors that work increasingly close to room temperature. A surprise in recent years was the discovery of high-temperature superconductivity in materials that have nothing in common with good metals. Consequently, understanding how such materials superconduct cannot be done with the standard building blocks of solid-state physics. This award supports research and education towards developing theoretical models to understand such superconductors. The PI will focus on analyzing a new class of recent experiments that offer unprecedented insight into the fundamental building blocks of the cuprate superconductors.In addition to training and mentoring graduate students, the PI will continue broad educational and outreach activities that include giving lectures to local middle-schools and public lectures to raise public awareness of physics.TECHNICAL SUMMARYWhile the strange metal has always stood as the basic obstacle in developing a theory of superconductivity in the cuprates, experiments designed to reveal the universal excitations that underly this state of matter have been nonexistent until now. The new experiments, momentum-resolved electron-energy loss spectroscopy (MEELS), measure the two-particle susceptibility and hence have all the many-body information needed to construct the dielectric function and also the single-particle electron self-energy. This award supports research and education towards extracting such information from the MEELS data. Special emphasis will be placed on comparison with optical measurements. Optical conductivity experiments measure the transverse dielectric response, while MEELS measures the longitudinal dielectric function. A key unanswered question is whether the two are equal. Certainly, they are expected to be equal in the limit of zero-momentum transfer, as any distinction between longitudinal and transverse dielectric functions disappears in this limit. However, the PI's analysis of the experimental data shows that this is not the case. The same analysis on other materials such as tantalum-diselinide, ruthenates, and even iron-pnictide superconductors reveals complete agreement between zero-momentum limits of the transverse and longitudinal dielectric functions. As this is the first instance where these two limits disagree, the cuprates represent an unprecendeted class of materials. Understanding of this discrepancy is at the heart of this project. The key question that arises is: Does the discrepancy between these two limits stand at the heart of strange-metal physics? Specific models will be studied to obtain a discrepancy between the two limits, and these models will be used to examine if they simultaneously explain the key characteristic of the strange metal, namely T-linear resistivity.In addition to training and mentoring graduate students, the PI will continue broad educational and outreach activities that include giving lectures to local middle-schools and public lectures to raise public awareness of physics.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.

通过使用超导导线来消除电网中的低效率导电可能会节省数十亿美元。德国埃森的AmpaCity项目就是这样一个例子。然而，实现这一目标的一个主要障碍是了解如何设计工作温度越来越接近室温的新超导体。近年来的一个令人惊讶的发现是，在与好金属毫无共同之处的材料中发现了高温超导性。因此，理解这种材料如何超导不能用固态物理学的标准构建块来完成。该奖项支持研究和教育，以开发理论模型来理解这种超导体。PI将专注于分析最近的一类新实验，这些实验为铜酸盐超导体的基本构建模块提供了前所未有的见解。除了培训和指导研究生，PI将继续开展广泛的教育和推广活动，包括为当地中产阶级举办讲座，虽然奇怪的金属一直是发展物理学理论的基本障碍，铜氧化物中的超导性，旨在揭示这种物质状态下的普遍激发的实验直到现在还不存在。新的实验，动量分辨电子能量损失谱（MEELS），测量两个粒子的磁化率，因此具有构建介电函数所需的所有多体信息，以及单粒子电子自能。该奖项支持从MEELS数据中提取此类信息的研究和教育。将特别强调与光学测量的比较。光学电导率实验测量横向介电响应，而MEELS测量纵向介电函数。一个关键的未回答的问题是两者是否相等。当然，在零动量转移的极限下，它们应该相等，因为在这个极限下，纵向和横向介电函数之间的任何区别都消失了。然而，PI对实验数据的分析表明，情况并非如此。对其他材料，如钽-二硒化物、钽酸盐，甚至铁-磷属元素化物超导体的相同分析揭示了横向和纵向介电函数的零动量极限之间的完全一致。由于这是这两个极限不一致的第一个例子，铜氧化物代表了一种前所未有的材料。理解这种差异是这个项目的核心。由此产生的关键问题是：这两个极限之间的差异是否是奇异金属物理学的核心？将研究特定的模型以获得两个极限之间的差异，这些模型将用于检查它们是否同时解释了奇怪金属的关键特性，即T线性电阻率。除了培训和指导研究生，PI将继续开展广泛的教育和推广活动，包括为当地中产阶级举办讲座，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。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Free at last: Bose metal uncaged

终于自由：Bose Metal 脱困

DOI：
10.1126/science.aaz9902
发表时间：
2019
期刊：
Science
影响因子：
56.9
作者：
Phillips, Philip W.
通讯作者：
Phillips, Philip W.

Extracting correlation effects from momentum-resolved electron energy loss spectroscopy: Synergistic origin of the dispersion kink in Bi2.1Sr1.9CaCu2O8+x

DOI：
10.1103/physrevb.103.035121
发表时间：
2020-10
期刊：
Physical Review B
影响因子：
3.7
作者：
E. Huang;K. Limtragool;C. Setty;A. Husain;M. Mitrano;P. Abbamonte;P. Phillips
通讯作者：
E. Huang;K. Limtragool;C. Setty;A. Husain;M. Mitrano;P. Abbamonte;P. Phillips

Anomalous diffusion and Noether's second theorem