Simple Molecular Systems at Ultrahigh Pressures

超高压下的简单分子系统

基本信息

批准号：
1809783
负责人：
Russell Hemley
金额：
$ 69.91万
依托单位：
George Washington University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-15 至 2019-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1809783&HistoricalAwards=false
关键词：
Simple Molecular Systems Ultrahigh Pressures

项目摘要

Nontechnical Abstract: The millions of atmospheres of pressure that can now be produced in the laboratory can impart profound effects on atoms and molecules, molding matter to make new materials with unprecedented properties. Conventional understanding fails to predict such effects, beginning with hydrogen, the first element in the Periodic Table, and extending to other "simple" elements. This project explores this new world of materials when compressed up to five million atmospheres (5 megabars or 500 gigapascals). A key property to be explored is superconductivity - the ability of a material to conduct electricity without resistance - at very high temperatures, including possibly room temperature and above. Advanced experimental techniques to study materials to very high pressures while at variable temperatures are employed to synthesize and characterize these materials, and theoretical and computational methods are used to interpret the results as well as to predict new materials and their properties to guide syntheses. The results have implications for fields beyond condensed-matter physics, including chemistry, advanced technology, planetary science, and astrophysics. An important goal is education and training of graduate students and undergraduates in the field. There is also a component that impacts locally STEM education and the public understanding of science.Technical Abstract: Pressure is not a simple thermodynamic parameter but an effective tool for the creation of exotic materials and phenomena not accessible at ambient conditions. Materials subjected to pressures up to several hundred gigapascals exhibit unexpected properties, including very high-temperature superconductivity, counterintuitive bonding patterns and electronic topological states, entirely new crystal structures, and potentially new physics. Investigations of materials at these conditions thus test both the limits of experimental techniques as well as fundamental theory. Addressing these questions in "simple" elemental and molecular systems at ultrahigh pressures, the project is divided into the following tasks: 1. Very High Tc Superconductivity; 2. Metallization and Novel Transitions in Dense Hydrogen; 3. High-Pressure Electrides; 4. Novel Interfacial Phenomena at Megabar Pressures; 5. Unconventional and Exotic Compounds; and 6. Methods and Technique Development. Each of the tasks involve tightly integrated experiment and computational theory. In particular, the experimental effort takes advantage of new developments in diamond-anvil techniques and capabilities at advanced radiation facilities to explore the nature of these materials in extreme conditions.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：现在实验室可以产生数百万个大气压，可以对原子和分子产生深远的影响，塑造物质以制造具有前所未有性能的新材料。传统的理解无法预测这种效应，从元素周期表中的第一个元素氢开始，一直延伸到其他“简单”元素。该项目探索了压缩至 500 万个大气压（5 兆巴或 500 吉帕）时的材料新世界。需要探索的一个关键特性是超导性，即材料在非常高的温度（可能包括室温及以上）下无电阻导电的能力。采用先进的实验技术在可变温度下研究非常高压的材料来合成和表征这些材料，并使用理论和计算方法来解释结果并预测新材料及其性能以指导合成。这些结果对凝聚态物理以外的领域具有影响，包括化学、先进技术、行星科学和天体物理学。一个重要目标是该领域研究生和本科生的教育和培训。还有一个因素会影响当地的 STEM 教育和公众对科学的理解。技术摘要：压力不是一个简单的热力学参数，而是创造在环境条件下无法实现的奇异材料和现象的有效工具。承受高达数百吉帕压力的材料表现出意想不到的特性，包括非常高温的超导性、违反直觉的键合模式和电子拓扑状态、全新的晶体结构以及潜在的新物理学。因此，在这些条件下对材料的研究既测试了实验技术的极限，也测试了基础理论的极限。为了解决超高压下“简单”元素和分子系统中的这些问题，该项目分为以下任务： 1. 极高 Tc 超导； 2. 浓氢中的金属化和新型转变； 3. 高压电极； 4. 兆巴压力下的新型界面现象； 5. 非常规和奇异化合物； 6. 方法和技术开发。每项任务都涉及紧密结合的实验和计算理论。特别是，实验工作利用了金刚石砧技术的新发展和先进辐射设施的能力来探索这些材料在极端条件下的性质。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。