Strange metals and the phases of quantum materials

奇异金属和量子材料的相

• 批准号: 2245246
• 负责人: Subir Sachdev
• 金额: $ 66万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2027-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2245246&HistoricalAwards=false
• 关键词: Strange; metals; phases; quantum; materials; Strange; metals; phases; quantum; materials

NONTECHNICAL SUMMARYThis award supports theoretical research which will examine the so-called "strange metal" phase of quantum matter, which is ubiquitous in systems in which the electron-electron interaction is very strong. Quantum mechanics was initially developed in the early twentieth century as a theory of the motion of a single electron around the nucleus of a hydrogen atom, but it can also describe the motion of a large number of electrons in metals and semiconductors, and this description was vital to the electronics revolution. The past few decades have witnessed the discovery of numerous "quantum materials" in which the role of quantum mechanics is more profound than previously thought and not well understood. In quantum materials, it is important to treat the motion of electrons collectively, and account for the entanglement between the different electrons. Most prominent among these new materials are the high temperature superconductors found in a series of compounds which contain copper, oxygen, and numerous other transition metals, which can conduct electricity without any loss of energy above a relatively high temperature. In this project, the PI and his team will develop a theory of electronic motion in such materials focusing especially on a regime of temperatures and electron density where the motion of electrons is most unlike those in conventional materials. This regime is often called the "strange metal" phase, and it is clear that the mutual entanglement of electrons plays an important role in bringing out the peculiar properties of this phase. This project will build on the successes of a model previously developed by the PI, which provides a simple setting in which the entanglement between the electrons is, in a sense, maximal, and yet the equations of quantum mechanics can be solved exactly. The PI and his collaborators have recently extended this model to a more realistic setting which maintains its solvability, and this yields an encouraging correspondence with observations on strange metals. This project will extend this understanding of the strange metal to other phases of quantum materials, including those exhibiting superconductivity at high temperatures and microstructures that consist of one-atom-thick sheets of carbon atoms stacked in various configurations on top of each other.This award will also contribute to the development of the scientific workforce by supporting the training of graduate students and postdoctoral associates in topics at the forefront of theoretical condensed matter physics. Furthermore, the PI will continue to pursue an active program of public lectures, interviews, colloquia, and lectures at schools for advanced graduate students.TECHNICAL SUMMARYThis award supports theoretical research which will examine the "strange metal" phase of quantum matter, which is ubiquitous in correlated electron systems, especially those that exhibit higher temperature superconductivity. A complete, quantitative understanding of the strange metal phase is essential to progress in the theory of quantum materials. The PI and his team have recently made progress on a theory of strange metals, which has the attractive features of being simple, universal, and broadly applicable across the range of correlated materials. In this project, the team will further develop the Sachdev-Ye-Kitaev model and related theories and compare the results quantitatively with numerous experimental probes. For the cuprate superconductors, the strange metal phase will be related to various neighboring phases, including the pseudogap, the superconductor, and the charge-ordered phases. Another focus area of this project is on graphene microstructures and will include studies of nanoscale graphene flakes and the manner in which they can exhibit signatures of the non-Fermi liquid of the Sachdev-Ye-Kitaev model. This award will also contribute to the development of the scientific workforce by supporting the training of graduate students and postdoctoral associates in topics at the forefront of theoretical condensed matter physics. Furthermore, the PI will continue to pursue an active program of public lectures, interviews, colloquia, and lectures at schools for advanced graduate 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.

非技术摘要这一奖项支持理论研究，该研究将检查所谓的“奇怪金属”阶段，这在电子 - 电子相互作用非常强的系统中无处不在。量子力学最初是在二十世纪初期开发的，它是氢原子核周围单个电子运动的一种理论，但它也可以描述金属和半导体中大量电子的运动，并且这种描述对电子革命而言至关重要。过去几十年来，发现了许多“量子材料”，其中量子力学的作用比以前想象的要深刻而又不太了解。在量子材料中，集体处理电子的运动并说明不同电子之间的纠缠非常重要。在这些新材料中最突出的是一系列包含铜，氧和许多其他过渡金属的高温超导体，这些化合物可以在相对较高的温度以上传导电力而不会损失能量。在这个项目中，PI和他的团队将在此类材料中发展一种电子运动理论，尤其是在温度和电子密度方面，电子运动的运动与传统材料中最不同。该机制通常称为“奇怪的金属”阶段，很明显，电子的纠缠在阐明此阶段的特性方面起着重要作用。该项目将建立在先前由PI开发的模型的成功基础上，该模型提供了一个简单的设置，在某种意义上，电子之间的纠缠是最大的，但是量子力学的方程式可以准确地解决。 PI和他的合作者最近将该模型扩展到了更现实的环境，该设置可保持其解决性，这对观察到奇怪金属的观察产生了令人鼓舞的对应。该项目将将对奇怪金属的理解扩展到量子材料的其他阶段，包括在高温和微观结构上表现出超导性的那些，这些材料由一片厚的碳原子组成的微观结构组成，这些碳原子在彼此之间堆叠了各种配置。这也将为培训培训的培训培训而促进毕业生的培训。凝结物理学。此外，PI将继续进行一项积极的公开讲座，访谈，讲习班和高级研究生学校讲座的计划。技术摘要这项奖项支持理论研究，该奖项将研究量子问题的“奇怪金属”阶段，这在相关电子系统中尤其是相关的电子系统中的无处不在，尤其是那些具有更高温度高温超级高度高度高度高度高度效果。对奇怪金属相的完整，定量的理解对于量子材料理论的进展至关重要。 PI和他的团队最近在一种奇怪的金属理论上取得了进步，该理论具有简单，通用且广泛适用于相关材料的诱人特征。在这个项目中，团队将进一步开发Sachdev-Ye-Kitaev模型和相关的理论，并将结果与​​许多实验探针进行定量比较。对于铜矿超导体，奇怪的金属相将与各种相邻的相关，包括伪随，超导体和电荷订购的相。该项目的另一个重点领域是石墨烯微结构，将包括对纳米级石墨烯薄片的研究以及它们可以表现出Sachdev-ye-Kitaev模型的非Fermi液体特征的方式。该奖项还将通过支持研究生和博士后伙伴的培训，这是理论上凝聚态物理学的最前沿的培训，从而为科学劳动力的发展做出贡献。此外，PI将继续在高级研究生的学校开展一项积极的公开讲座，访谈，教区和讲座的计划。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准来评估的。