Ab Initio Prediction of Properties of Complex Solids Having Short-Range Order and Partial Long-Range Order

技术综述：该奖项支持理论和计算材料理论和教育，重点是电子结构。本研究发展了一种全电子热力学密度泛函理论来预测包含短程有序或部分长程有序的能量和电子变化。为了预测短程有序而发展起来的理论利用了电子巨势。预测晶体结构、晶体缺陷和每个结构中的原子排列，提高了预测具有“复杂的”多亚晶格和多组分组成的新技术材料的性能的能力。计划对表现出不同程度的局部环境相关性(或短程有序)的复杂材料进行处理，涉及原子、空位、磁矩。这种有序性可以通过衍射实验来测量，并在钢、耐火材料、电池材料和氧化物中观察到。该理论采用动力团簇近似，这是为关联电子问题而开发的，在PI的多重散射电子结构代码中实现。所提出的工作将产生一种新的热力学密度泛函理论电子结构代码，处于计算电子结构方法的前沿。基于密度泛函理论的新方法将同时处理有限温度下的电子和原子自由度，包括电子和原子的熵，并直接确定短程有序及其对能级、电子结构和技术有用性质的影响。各种金属合金和氧化物材料将为检验代码提供试验场，为材料研究提供方向。这项工作将是研究生培训的一部分。非技术总结：该奖项支持理论和计算材料理论和教育，旨在为基于计算机的材料模拟和材料性能预测增加新的能力。该项目代表着对其他方法施加的限制的进步，例如，必须假设一个由完美定位和静止的原子组成的无限阵列。有了这些发展，材料的性质可以通过包含具有原子尺度无序的真实结构来计算，并且可以捕捉到温度的重要影响。各种金属合金和氧化物材料将为测试材料研究的代码和方向提供一个试验场。该项目直接为更广泛的材料研究社区的网络基础设施做出贡献，因为计算机代码将提供给社区。该项目提供了对有望用于商业应用的新材料的特定材料的预测，以及对控制其性能的因素的基本了解。阐明这些因素将允许对属性进行“智能”定制。该项目包括研究生和本科生，他们有机会参与这项尖端研究。

TECHNICAL SUMMARY:This award supports theoretical and computational materials theory and education with a focus on electronic structure. This research develops an all-electron thermodynamic density-functional theory to predict the energy and electronic changes incorporating short-range order or partial long-range order. The theory developed to predict short-range order employs the electronic grand potential. Predicting crystal structure, crystalline defects and atomic arrangements within each structure enhance the ability to predict properties of new technological materials with "complex" multi-sublattice and multi-component make up. Treatment of complex materials that exhibit various levels of local environmental correlations (or short-range order) involving atoms, vacancies, magnetic moments is planned. Such order may be measured by diffraction experiments and observed in steels, refractory and battery materials, and oxides. The theory employs the Dynamical Cluster Approximation, developed for correlated-electron problems, implemented within the PI's multiple-scattering electronic-structure code. The proposed work will produce a novel thermodynamic density functional theory electronic structure code, at the forefront of computational electronic-structure methods. The new DFT-based method will simultaneously addresses electronic and atomic degrees of freedom at finite temperature, include both electronic and atomic entropy, and directly determine the short-range order and its effects on energetics, electronic-structure and technologically useful properties. Various metal alloys and oxide materials will provide a proving ground for testing the code and directions for materials reserch. The effort will be part of the training of graduate students.NON-TECHNICAL SUMMARY:This award supports theoretical and computational materials theory and education that aims to add new capability to computer-based simulation of materials and the prediction of their properties. The project represents an advance forward from limitations imposed by other approaches, for example having to assume an infinite array of perfectly positioned and stationary atoms. With these developments, materials properties could be calculated with the inclusion of realistic structures that have atomic-scale disorder and where important effects of temperature can be captured. Various metal alloys and oxide materials will provide a proving ground for testing the code and directions for materials reserch.This project contributes directly to the cyberinfrastructure of the broader materials research community, since computer codes will be made available to the community. The project provides materials-specific prediction of novel materials that are promising for commercial application, as well as a fundamental understanding of the factors that control their properties. Elucidating these factors will permit "intelligent" tailoring of properties. The project includes students at graduate and undergraduate level who get an opportunity to participate in this cutting-edge research.