Theoretical Spectroscopy and Thermodynamics of Correlated Electron Materials

非技术总结新功能材料的发现对技术进步和经济发展都是至关重要的，先进的计算方法正在加速这一领域的进展。该奖项支持研究和教育，以加快我们对复杂材料的理解，复杂材料表现出磁性、超导和强关联电子行为等量子效应之间的突出竞争。在更简单的材料中，以独立粒子系统的模型表示就足够了，先进的方法使大规模模拟现实系统的物理性质成为可能。对于表现出相关电子行为的材料，其中一个电子的行为强烈依赖于材料中其他电子的行为，动态平均场理论方法使基本材料性质的计算变得实用和准确。这个项目的重点是开发用计算机模拟这种复杂材料并能预测材料性能的软件。重点是提高理论的精度，并开发新的理论光谱学工具，这将使预测相关固体的精确晶体结构，以及预测使用中子和X射线散射实验技术进行的实际光谱测量成为可能。该项目将导致开发算法和软件，这些算法和软件将被整合到开放源码包中，随后将提供给更广泛的研究社区。这些工具将帮助材料科学界找到有希望的合成候选材料，这应该会进一步使理论辅助的材料发现和设计成为可能。作为该项目的一部分，还将对初级研究人员进行培训和指导，为发展科学工作力量做出贡献。技术摘要：在寻找具有增强物理性能的新材料时，发展广泛的计算表征能力是至关重要的。该奖项支持开发一些理论光谱工具的研究和教育，这些工具可以与电子结构工具结合使用。后者是基于动力平均场理论(在以前的NSF支持下开发的)，并能够使用第一原理方法对材料性质进行理论预测。在这个项目中将开发的光谱工具和方法包括：i)使用晶胞中所有原子上的力来松弛复杂的晶体结构，这将使预测复杂的晶体结构成为可能；ii)将力的计算扩展到具有大自旋-轨道耦合的材料；iii)开发一种工具来预测具有强耦合晶体和电子结构的系统的相变；iv)开发一种工具来计算相关材料中的声子；五)开发适当考虑核心-空穴相互作用的X射线散射光谱学。这些工具将向更广泛的科学界提供，因为它们将被纳入PI的电子结构软件包，该软件包被广泛使用，并作为开放源码分发；见：http://hauleweb.rutgers.edu/tutorials/.这项研究的总体目标是建立一个描述相关材料物理性质的预测框架，并通过与材料科学家的密切合作来实验验证它，以测试计算理论的预测，并在不一致的领域改进它。作为该项目的一部分，还将对初级研究人员进行培训和指导，以促进科学工作的发展。该奖项反映了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。

NONTECHNICAL SUMMARYDiscoveries of new functional materials are crucial for technology advancement as well as for economic development, and advanced computational methods are accelerating progress in this area. This award supports research and education towards the acceleration of progress in our understanding of complex materials, which manifest prominent competition between quantum effects such as magnetism, superconductivity, and strongly correlated electron behavior.In simpler materials, for which model representations in terms of a system of independent particles suffices, advanced methods have enabled large-scale simulations of the physical properties of realistic systems. For materials exhibiting correlated electron behavior, where the behavior of one electron is strongly dependent on that of other electrons in the material, the Dynamical Mean Field Theory method has enabled practical and accurate calculations of basic material properties. This project focuses on the development of software that simulates such complex materials with a computer, and which can predict material properties. The focus is in improving the precision of the theory, and in developing new theoretical spectroscopy tools, which will enable the prediction of the precise crystal structures of correlated solids, and the prediction of actual spectroscopic measurements made using neutron and x-ray scattering experimental techniques.The project will lead to the development of algorithms and software that will be incorporated in open-source code packages, which subsequently will be made available to the wider research community. These tools will help the materials science community to find promising material candidates for synthesis, which should further enable theory-assisted material discovery and design. Training and mentorship of junior researchers will also take place as part of the project, contributing to the development of scientific workforce.TECHNICAL SUMMARY: In the search for new materials with enhanced physical properties it is crucial to develop broad capabilities for computational characterization. This award supports research and education towards the development of a number of theoretical spectroscopic tools, which can be used in combination with electronic structure tools. The latter are based on Dynamical Mean Field Theory (developed under previous NSF support), and enable theoretical prediction of material properties using first-principles methods. The spectroscopic tools and methods that will be developed in this project include: i) relaxation of complex crystal structures using forces on all atoms in the unit cell, which will enable prediction of complex crystal structures; ii) extension of the calculation of forces to materials with large spin-orbit coupling; iii) developing a tool to predict phase transitions in systems with strongly coupled crystal- and electronic structure; iv) developing a tool to calculate phonons in correlated materials; v) developing x-ray scattering spectroscopy that properly takes into account the core-hole interaction.These tools will be made available to the broader scientific community as they will be incorporated in the PI's electronic structure software package, which is widely used, and is distributed as open-source; see: http://hauleweb.rutgers.edu/tutorials/. The overall goal of the research is to build a predictive framework for describing the physical properties of correlated materials, to experimentally validate it, by close collaboration with material scientists to test the predictions of the computational theory, and to improve it in the areas of disagreement. Training and mentorship of junior researchers will also take place as part of the project, contributing to the development of scientific workforce.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.