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

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

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.