ITR: Development of Computational Time-Dependent Density-Functional Theory Methods for the Study of Electronic Excitations in Correlated Materials

该奖项隶属于信息技术研究计划，支持材料动态相关性的基础计算和理论研究，包括算法开发。探索的方法包括时相关密度泛函理论（TDDFT）和Baym-Kadanoff守恒近似。这项工作的目的是在新的计算方法和对涉及绝缘体、过渡金属、稀土金属氢化物和过渡金属氧化物的非平凡固态原型的动态电子相关性的见解之间建立协同作用。计算动态电荷密度和自旋密度响应函数；这些量直接映射到实验损失函数中，并包含唯一的相关特征。实现了时变优化势能法。这种方法依赖于将交换相关势表示为单电子轨道的函数，是自相互作用自由的。因此，它为相关材料的研究提供了一种很有前途的方法。在描述反铁磁绝缘体基态方面已被证明是成功的“混合泛函”也将被探索。TDDFT也将在不调用线性响应机制的情况下实现，通过在实空间网格上显式地求解时间相关的Kohn-Sham方程，在时间网格上传播状态。Baym-Kadanoff守恒近似也将被实施和探索。所提出的理论和计算将有助于现代计算材料物理学研究生和博士后的教育。来自弱势背景的大学生将在夏季通过UTK的Ronald McNair项目积极参与研究。该奖项隶属于信息技术研究计划，支持基础计算和理论研究，包括在绝缘体、过渡金属、稀土金属氢化物和过渡金属氧化物中动态电子相关性的算法开发。这项工作包括发展新的计算方法和探索复杂的理论形式，目的是在实际材料中建立电子动力学和输运的定量理论。该工作还将为材料非弹性x射线散射的同步实验研究提供理论指导。虽然这是基础研究，但所开发的计算方法可能会支持材料和光电子器件技术的未来发展

This award under the Information Technology Research initiative supports fundamental computational and theoretical research, including algorithm development, on dynamical correlations in materials. Methods to be explored include time-dependent density functional theory (TDDFT) and Baym-Kadanoff conserving approximations.An aim of this work is to establish a synergy between novel computational methods and insight into the dynamical electronic correlations in non-trivial solid-state archetypes involving insulators, transition metals, rare-earth metal hydrides, and transition-metal oxides. Dynamical charge-density and spin density response functions will be calculated; these quantities map directly into experimental loss functions, and contain unique signatures of correlation. The time-dependent optimized-potential method will be implemented. This method, which relies on a representation of the exchange-correlation potential as a functional of one-electron orbitals, is self-interaction free. So, it represents a promising approach for the study of correlated materials. "Hybrid functionals," which have proved successful in the description of the ground state of antiferromagnetic insulators will also be explored. TDDFT will also be implemented without invoking the linear-response regime, by explicitly solving the time-dependent Kohn-Sham equation on a real-space grid, propagating the states on a time grid. Baym-Kadanoff conserving approximations will also be implemented and explored.The proposed theoretical and computational will contribute to the education of graduate students and postdocs in modern computational materials physics. College students from disadvantaged backgrounds will be actively recruited for research participation during the summers through the Ronald McNair program at UTK. %%%This award under the Information Technology Research initiative supports fundamental computational and theoretical research, including algorithm development on dynamical electronic correlations in insulators, transition metals, rare-earth metal hydrides, and transition-metal oxides. The work involves the development of new computational methods and the exploration of sophisticated theoretical formalism with an aim to forge a quantitative theory of electron dynamics and transport in real materials. The work will also contribute theoretical guidance to concurrent experimental investigations of materials using inelastic x-ray scattering. While this is fundamental research, the computational methods developed may support future advances in materials and optoelectronic device technologies.***