Metallization of Hydrogen-Rich Materials: Predicting Novel Superconductors

材料研究部和网络基础设施办公室为该奖项提供资金。它支持理论研究和教育，这将导致新的超导体的合理设计。人们认为，在足够的压缩下，由于压力引起的填充和未填充带的加宽以及它们最终的重叠，氢将变成金属。理论预测表明，该相可能是高温超导体。不幸的是，氢在迄今为止达到的最高静压下不会变成金属。现在，人们对开发化学启发的策略产生了巨大的兴趣，这些策略可以显着降低金属化所需的压力。两个例子是：该PI将侧重于预测具有不寻常的化学计量的离子和共价多金属化合物的结构，这些化合物在压力下是稳定的和金属的。一个进化算法，接口的第一性原理电子结构程序将被用于实现这一目标。理论和实验研究已经表明，特定的锂和硅含氢材料在挤压时变得稳定，并且它们很可能是实验可实现压力下的金属。这项工作将导致对富氢材料在压力下的化学，电子结构和潜在超导性的更深入理解。PI旨在确定哪些因素对促进这些系统在温和压缩下的金属化是重要的，确定最有利的化学计量和结构，它们的性质，以及在商业上可获得的压力下化学稳定这些相的方法。 PI将开发一种进化算法XtalOpt，用于预测最稳定系统的结构。该算法将免费提供给材料科学，物理和化学社区，作为免费可视化工具“Avogadro”的扩展。“它将在GNU公共许可证下发布，并与几个广泛用于研究固体的电子结构软件包接口。 该代码将利用现有的网络基础设施，并将高度模块化，并明确记录，以促进进一步的发展。非技术总结材料研究部门和网络基础设施办公室为该奖项提供资金。它支持理论研究和教育，其最终目标是使用概念，理论和计算技术来设计新的超导材料。在超导体中，电流可以流动而不耗散。用高温超导电力线取代铜线可能会对美国的电力基础设施产生巨大影响。不幸的是，所有已知的超导体材料都只在非常低的温度下才能做到。理论工作已经预言，在压力下，最简单的元素氢将变成金属，并在室温附近超导。不幸的是，使氢金属化所需的压力比地球中心的压力大。PI将开发化学灵感策略，可以显着降低获得金属氢所需的压力。最先进的计算技术将被用来预测富氢系统在压力下的结构和性质。PI的计算将确定这些材料是否有可能成为超导体，并将建议这些相如何在常压下化学稳定。将开发一种进化算法XtalOpt，以预测最稳定系统的结构。该算法将免费提供给材料科学，物理和化学社区，作为免费可视化工具“Avogadro”的扩展。“它将在GNU公共许可证下发布，并与几个广泛用于研究固态材料的计算机程序接口。

TECHNICAL SUMMARYThe Division of Materials Research and the Office of Cyberinfrastrcture contribute funds to this award. It supports theoretical research and education which will lead towards the rational design of novel superconductors. It is thought that under sufficient compression hydrogen will become metallic due to the pressure-induced broadening of filled and unfilled bands, and their eventual overlap. Theoretical predictions indicate that this phase may be a high temperature superconductor. Unfortunately, hydrogen does not become metallic at the highest static pressures reached so far. There is now tremendous interest in developing chemically inspired strategies which could significantly decrease the pressure necessary for metallization. Two examples are: combination with tetravalent atoms, as in the group 14 hydrides, or by the addition of an electropositive element.The PI will focus on predicting the structures of ionic and covalent polyhydrides with unusual stoichiometries that are stable, and metallic under pressure. An evolutionary algorithm, interfaced with a first-principles electronic structure program will be employed towards this end. Already, theoretical and experimental research has shown that specific lithium and silicon bearing hydrogen materials become stable when squeezed, and it is likely that they are metals at experimentally achievable pressures. This work will lead to a deeper understanding of the chemistry, electronic structure and potential superconductivity of hydrogen-rich materials under pressure. The PI aims to determine which factors are important in facilitating the metallization of these systems under mild compression, determine the most favorable stoichiometries and structures, their properties, and ways to chemically stabilize these phases at commercially accessible pressures. The PI will develop an evolutionary algorithm, XtalOpt, which will be used to predict the structures of the most stable systems. This algorithm will be made freely available to the materials science, physics and chemistry communities as an extension to the free visualization tool "Avogadro." It will be released under the GNU Public License, and interfaced with several electronic structure packages which are widely used to study solids. The code will make use of already existing cyberinfrastructure, and will be highly modular, and clearly documented so as to facilitate further development.NONTECHNICAL SUMMARYThe Division of Materials Research and the Office of Cyberinfrastrcture contribute funds to this award. It supports theoretical research and education whose ultimate goal is to use concepts, and theoretical and computational techniques to design new superconducting materials. In a superconductor electric current can flow without dissipation. Replacing copper wires with high temperature superconducting power lines could have a tremendous impact on the electrical power infrastructure of the USA. Unfortunately, all of the materials which are known to behave as superconductors do so only at very low temperatures. Theoretical work has predicted that under pressure the simplest element hydrogen will become metallic, and superconducting near room temperature. Unfortunately, the pressures necessary to metalize hydrogen are greater than those at the center of the earth. The PI will develop chemically inspired strategies which could significantly decrease the pressure necessary to achieve metallic hydrogen. State-of-the-art computational techniques will be employed to predict the structures and properties of hydrogen rich systems under pressure. The PI's computations will determine if these materials could potentially be superconductors, and will suggest how these phases may be chemically stabilized at normal pressures. An evolutionary algorithm, XtalOpt, will be developed in order to predict the structures of the most stable systems. This algorithm will be made freely available to the materials science, physics and chemistry communities as an extension to the free visualization tool "Avogadro." It will be released under the GNU Public License, and interfaced with several computer programs which are widely used to study solid state materials.