Superconducting and Metal-Insulator Transitions in Quasi-Two-Dimensional Strongly Correlated Materials

准二维强关联材料中的超导和金属-绝缘体转变

• 批准号: 2104193
• 负责人: Dragana Popovic
• 金额: $ 48.31万
• 依托单位: Florida State 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 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2104193&HistoricalAwards=false
• 关键词: Superconducting; Metal; Insulator; Transitions; Quasi

NONTECHNICAL:Electronic properties of many new materials with potentially great technological importance are dominated by interactions among charge carriers. Those correlations give rise to a variety of phenomena, including the emergence of novel states of matter and transitions between different phases, such as metal to insulator or superconductor to normal. However, microscopic mechanisms underlying these transitions and the nature of various phases in such strongly correlated systems are not well understood. This research addresses fundamental questions about superconducting and metal-insulator transitions in two classes of layered, strongly correlated materials, copper-oxide high-temperature superconductors and a new series of organic systems, by performing measurements of charge transport over a wide range of temperatures and magnetic fields. The results of this project are crucial for understanding of strongly correlated materials, which will benefit society by ultimately influencing the development of science and technology. A key component of the project is education and training of graduate students for future careers in academia, national laboratories, and industry. It also incorporates various activities to broaden the participation of underrepresented groups in the areas of science, technology, engineering, and mathematics, outreach to general public, and impact on research infrastructure.TECHNICAL:This project addresses several fundamental questions in the physics of strongly correlated materials, such as unconventional superconductivity and the Mott metal-insulator transition in quasi-two-dimensional systems. Since anomalous transport properties are one of the key characteristics of strongly correlated materials, experiments involve electrical transport, including time-resolved protocols. Studies focus on two classes of quasi-two-dimensional systems, cuprates and newly synthesized substitutional series of quasi-two-dimensional organics. In both cases, unconventional superconductivity emerges as a result of tuning through the Mott transition by varying doping or chemical pressure, respectively. In cuprates, the goal is to probe the destruction of superconductivity by high magnetic fields and to clarify the respective roles of spin and charge orders, disorder, and quantum phase fluctuations, as a function of doping. In organics, the focus is on understanding unconventional superconductivity by exploring both thermal and magnetic-field-tuned superconducting transitions. In addition, the Mott metal-insulator transition and the role of spin liquid excitations are probed using time-resolved techniques. The knowledge gained from this project is essential for further development of condensed matter 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.

非技术：许多具有潜在重大技术重要性的新材料的电子性质是由电荷载流子之间的相互作用决定的。这些关联导致了各种现象，包括新的物质状态的出现和不同相之间的转变，如金属到绝缘体或超导体到正常。然而，这些转变背后的微观机制以及这种强关联系统中不同阶段的性质还没有被很好地理解。这项研究通过测量在广泛的温度和磁场范围内的电荷传输，解决了两类层状、强相关材料、铜氧化物高温超导体和一系列新的有机系统中的超导和金属-绝缘体相变的基本问题。该项目的结果对于理解强相关材料至关重要，这将最终影响科学和技术的发展，从而造福社会。该项目的一个关键组成部分是对研究生进行教育和培训，为未来在学术界、国家实验室和工业领域的职业生涯做准备。它还包括各种活动，以扩大未被充分代表的群体在科学、技术、工程和数学领域的参与，向普通公众推广，以及对研究基础设施的影响。技术：这个项目解决了强相关材料物理学中的几个基本问题，如非传统超导和准二维系统中的Mott金属-绝缘体转变。由于反常的输运性质是强关联材料的关键特征之一，实验涉及到电子输运，包括时间分辨协议。研究主要集中在两类准二维体系，即铜酸盐和新合成的准二维有机化合物的置换系列。在这两种情况下，非传统超导电性的出现分别是通过改变掺杂或化学压力通过Mott转变进行调谐的结果。在铜酸盐中，目标是探索强磁场对超导电性的破坏，并澄清自旋和电荷顺序、无序和量子位相波动作为掺杂的函数各自所起的作用。在有机学中，重点是通过探索热和磁场调谐的超导转变来理解非传统超导电性。此外，我们还用时间分辨技术研究了Mott金属-绝缘体的转变和自旋液体激发的作用。从这个项目中获得的知识对凝聚态物理的进一步发展至关重要。这一奖项反映了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。