Theoretical Spectroscopy and Thermodynamics of Correlated Electron Materials

新功能材料的发现对于技术进步和经济发展至关重要，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，以加速我们对复杂材料的理解，这些材料表现出量子效应之间的突出竞争，如磁性，超导性和强相关电子行为。在简单的材料中，独立粒子系统的模型表示就足够了，先进的方法使现实系统的物理特性的大规模模拟成为可能。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实际和准确的计算成为可能。该项目的重点是开发用计算机模拟这种复杂材料的软件，并可以预测材料性能。重点是提高理论的精度，开发新的理论光谱工具，这将使预测相关固体的精确晶体结构成为可能，并预测使用中子和X射线散射实验技术进行的实际光谱测量。该项目将导致开发算法和软件，这些算法和软件将被纳入开源代码包，随后将提供给更广泛的研究界。这些工具将帮助材料科学界找到有前途的材料候选人进行合成，这将进一步实现理论辅助的材料发现和设计。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，为科学工作者的发展做出贡献。技术概要：在寻找具有增强物理性能的新材料时，开发广泛的计算表征能力至关重要。该奖项支持研究和教育，以开发一些理论光谱工具，这些工具可以与电子结构工具结合使用。后者基于动态平均场理论（在以前的NSF支持下开发），并使用第一原理方法对材料特性进行理论预测。该项目将开发的光谱工具和方法包括：一）利用作用在晶胞中所有原子上的力来弛豫复杂的晶体结构，这将能够预测复杂的晶体结构;二）将力的计算扩展到具有大自旋轨道耦合的材料;三）开发一种工具来预测具有强耦合晶体和电子结构的系统中的相变; iv）开发一种计算相关材料中声子的工具; v）开发适当考虑核-空穴相互作用的X射线散射光谱。这些工具将被更广泛的科学界使用，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，并作为开源软件分发;见：http://hauleweb.rutgers.edu/tutorials/。该研究的总体目标是建立一个用于描述相关材料物理特性的预测框架，通过与材料科学家密切合作来测试计算理论的预测，并在不一致的领域进行改进。作为项目的一部分，还将对初级研究人员进行培训和指导，为科学工作者的发展做出贡献。该奖项反映了NSF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。

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.