Renewal: Simple Molecular Systems at Ultrahigh Pressures

非技术描述：压力不仅是日常生活中许多方面熟悉的简单参数，而且也是一种有效的工具，可以用来创造在普通条件下无法获得的奇异材料。在许多情况下，当日常物质在实验室中受到极端压力时，例如在地球核心的那种压力下，或在大气压力的200万倍下，就可以合成全新的材料。一个例子是超导性——在新发现的含有大量氢的材料中无电阻导电的能力。事实上，这些材料已被证明在室温下甚至可能高于室温时具有超导性。该项目从根本上研究了这些材料和相关材料，并以制造可用于现代技术的室温超导体为目标。更广泛地说，对高压下这些材料和相关材料的研究有望为广泛的科学领域提供信息，从化学和物理到材料科学和工程，再到行星科学和天体物理学。这一发现还可能导致氢储存和分离机制的改进，从而影响未来的能源需求。在国家用户设施开发的技术提供给科学界。拟议项目的一个重要组成部分是教育和培训下一代研究人员，特别是那些来自科学和技术学科中代表性不足的许多群体的研究人员，例如在伊利诺伊大学芝加哥分校，这是一个为少数民族服务的机构。技术描述：该项目支持300 GPa （3mbar）以上压力下简单元素和分子系统的基本相互作用研究。采用了一系列最先进的实验和理论技术来研究所选材料的结构和输运特性，重点研究了具有高温超导性和其他奇异物理特性的低原子序数(Z)材料。采用理论和计算方法预测高压下的稳定成分和结构，并采用先进的高压-温度P-T方法对这些材料进行原位合成和表征。这项工作的重点是氢主导材料，如超氢化物，我们的小组已经证明，在室温附近，甚至可能高于室温，在兆巴压力下，表现出非常高的Tc超导性。理论和计算被用来解释结果和指导后续的合成和表征。这种经过验证的联合理论-实验“设计材料”方法导致了我们之前的发现，它被应用于解决新的问题，包括扩大组成范围和探索的压力-温度-磁场的极端条件，以及理解潜在的传输机制，包括这些低z系统的量子效应。所有相关的实验和理论技术，包括新的建模和仿真方法，都被引入到这些材料的研究中。特别是，国家用户设施的新能力和新兴能力被应用于用新的综合方法探测材料的结构、电子和传输特性。这项工作有可能推进我们对极端条件下物质的理解，从而改善我们对控制材料行为的基本相互作用的理解，并导致为实际应用创造新的有用材料。该奖项反映了美国国家科学基金会的法定使命，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。

Non-technical Description: Pressure is not only simple parameter familiar in many aspects of everyday life, but it is also an effective tool that can be used to create exotic materials not accessible under ordinary conditions. In many cases, altogether new materials can be synthesized when everyday substance are subjected to extreme pressures in the laboratory, for example at the kinds of pressure found in the core of Earth, or 2 million times atmospheric pressure. An example is superconductivity – the ability to conduct electricity without resistance – in newly discovered materials that contain a great deal of hydrogen. Indeed, these materials have been shown to superconduct at, and possibly above, room temperature. This project investigates these and related materials, both fundamentally and with the goal of making room-temperature superconductors that could be used in modern technology. More broadly, this study of these and related materials at high pressure is expected to inform a broad range of scientific fields, from chemistry and physics, to materials science and engineering, to planetary science and astrophysics. The findings could also lead to improved mechanisms of hydrogen storage and separation that could impact future energy needs. The techniques developed at national user facilities are made available to the scientific community. An important component of the proposed project is the education and training of the next generation of researchers, particularly those from many groups that are underrepresented in scientific and technical disciplines, for example at the University of Illinois Chicago, which is a Minority-Serving Institution. Technical Description:This project supports the study of fundamental interactions in simple elemental and molecular systems to pressures above 300 GPa (3 Mbar). A full range of state-of-the-art experimental and theoretical techniques are used to investigate the structural and transport properties of selected materials, with a focus on low-atomic number (Z) materials that exhibit very high-temperature superconductivity and other exotic physical properties. Theoretical and computational methods are used to predict stable compositions and structures at high pressures, and advanced high pressure-temperature P-T methods are employed to synthesize and characterize these materials in-situ. The focus of this work is hydrogen-dominant materials, such as superhydrides, that our group has shown to exhibit very high Tc superconductivity in the vicinity of, and possibly above, room temperature, at megabar pressures. Theory and computation are used to interpret the results and guide subsequent synthesis and characterization. This proven joint theoretical-experimental ‘materials by design’ approach that led to our previous discoveries are applied to address new questions that include expanding the range of compositions and extreme conditions of pressure-temperature-magnetic field explored and understanding underlying transport mechanisms, including quantum effects expected for these low-Z systems. The full range of relevant experimental and theoretical techniques, including new modeling and simulation methods, are brought to bear on the study of these materials. In particular, new and emerging capabilities at national user facilities are applied to probe the structural, electronic, and transport properties of materials with new integrated approaches. The work has the potential to advance our understanding of matter at extreme conditions, and thereby improve our picture of the fundamental interactions that govern the behavior of materials, as well as lead to the creation of new useful materials for practical applications.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.