Theoretical Solid State Physics

该奖项支持理论和计算研究和教育，以了解材料和纳米结构在微观水平上的电子，光学和磁性。凝聚态物质的迷人特性和现象来自构成材料的电子和离子的相互作用，其中许多是现代技术的核心，如电子学，光电子学，光电子学和其他能量转换设备。通过改变化学成分或将材料限制在沿着一个或多个维度的纳米尺度，这些性质通常会发生显著改变或出现新现象。该项目的重点是使用量子理论，建模和模拟来解释和预测新材料和纳米结构的存在和性质。 新的理论方法和现代高性能（大规模并行）计算机的可用性使团队能够获得原子薄（沿着一个或多个维度）材料，纳米结构，界面和缺陷现象，新超导体和光催化材料的行为的第一原理（即没有经验参数）解释和预测。教育部分的重点是培训学生（研究生和本科生）和博士后研究员，以便在当前的量子技术革命中使用材料进行研究和开发。研究结果发表在科学期刊上，并在该团队的网站上发表。从该项目开发的计算工具被纳入几个软件包，这些软件包在网上免费提供给研究界。另一项教育活动与公众教育有关，通过在非专业媒体上发表文章和采访以及PI和co-PI的公开讲座进行。技术摘要该奖项支持理论和计算研究和教育，通过执行第一性原理量子计算，在微观水平上理解材料和纳米结构的电子，传输，光学和磁性特性。 调查的主题包括：i）原子薄的一维和二维系统的结构和动力学性质; ii）降维系统和大块材料中的新颖光学、拓扑和磁性性质;以及iii）电子-声子相互作用、超导性和相关现象。主要目标是使用多体量子理论和新的概念，如那些从拓扑结构来解释和预测的真实的材料，特别是低维系统的性能。重点放在现实的模型，与实验人员的密切合作，调查和生产新的和有用的材料的建议，新的理论和计算方法的发展，以及与结构，电子，磁性，超导，运输和光学性能的预测。 基于多体量子理论的最新技术被用于实现真实的材料的精确第一性原理计算。特别是，从头算赝势方法和总能量技术内的密度泛函形式主义（DFT）计算基态性质。激发态（光谱）的现象进行了研究，使用第一原理自能方法的基础上的GW近似的准粒子激发和从头算两粒子绿色的功能方法的基础上的Bethe-Salpeter方程的光激发。磁行为和电子-声子耦合现象的研究，超越了目前的最先进的，分别使用该团队新开发的重整化自旋波方法和GW微扰理论方法进行。其他研究依赖于分子动力学或蒙特卡罗模拟，BCS理论和标准多体理论的扩展。第一性原理计算在适当的时候增加了模型哈密顿研究，特别是为了理解拓扑效应和具有强电子关联的系统。教育部分侧重于培训学生（研究生和本科生）和博士后研究员，以便在当前量子技术革命中使用材料进行研究和开发。研究结果发表在科学期刊上，并在该团队的网站上发表。从该项目开发的计算工具被纳入几个软件包-伯克利GW，PARATEC和EPW-这是免费提供给研究社区的网络。另一项教育活动与公众教育有关，通过在非专业媒体上发表的文章和访谈以及PI和co-PI的公开讲座来完成。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 Summary This award supports theoretical and computational research and education towards understanding the electronic, optical, and magnetic properties of materials and nanostructures at the microscopic level. The fascinating properties and phenomena of condensed matter emerge from mutual interactions of the electrons and ions that constitute the material, many of which are central to modern technologies such as electronics, optoelectronics, photovoltaics, and other energy conversion devices. These properties can often be dramatically altered or new phenomena emerge from varying the chemical composition or confining the materials to nanometer scales along one or more dimensions. This project is centered on using quantum theory, modeling, and simulations to explain and predict the existence and properties of novel materials and nanostructures. New theoretical approaches and the availability of modern high performance (massively parallel) computers allow the team to obtain first-principles (i.e. with no empirical parameters) explanations and predictions of the behavior of atomically thin (along one or more dimensions) materials, nanostructures, interfacial and defect phenomena, new superconductors, and photocatalytic materials. The educational components are focused on training of students (graduate and undergraduate) and postdoctoral fellows for research and development in using materials in the current quantum technological revolution. The research findings are published in scientific journals as well as presented on the team's website. The computational tools developed from the project are incorporated into several software packages, which are made freely available on the web to the research community. Another educational activity is related to public education, which is done through articles and interviews published in lay media and via public lectures by the PI and co-PI.Technical SummaryThis award supports theoretical and computational research and education towards understanding the electronic, transport, optical, and magnetic properties of materials and nanostructures at the microscopic level by performing first-principles quantum calculations. Topics investigated include: i) structural and dynamical properties of atomically thin one- and two-dimensional systems; ii) novel optical, topological, and magnetic properties in reduced dimensional systems and bulk materials; and iii) electron-phonon interactions, superconductivity, and associated phenomena. The major objective is to use many-body quantum theory and new concepts such as those from topology to explain and predict the properties of real materials, in particular for lower dimensional systems. Emphasis is placed on realistic models, close collaborations with experimentalists, investigations and suggestions for producing novel and useful materials, development of new theoretical and computational approaches, and predictions related to structural, electronic, magnetic, superconducting, transport and optical properties. State-of-the-art techniques based on many-body quantum theory are used to enable accurate first-principles calculations for real materials. In particular, the ab initio pseudopotential method and total energy techniques are applied within the density functional formalism (DFT) to compute ground-state properties. Excited-state (spectroscopic) phenomena are investigated using a first-principle self-energy approach based on the GW approximation for quasiparticle excitations and an ab initio two-particle Green's function method based on the Bethe-Salpeter equation for optical excitations. Studies of magnetic behaviors and electron-phonon coupling phenomena, going beyond the current state of the art, are carried out using the team's newly developed renormalized spin wave method and the GW perturbation theory method, respectively. Other studies rely on molecular dynamics or Monte Carlo simulations, BCS theory, and extensions of standard many-body theory. The first-principles calculations are augmented with model Hamiltonian studies when appropriate, especially for understanding topological effects and systems with strong electron correlations.The educational components are focused on training of students (graduate and undergraduate) and postdoctoral fellows for research and development in using materials in the current quantum technological revolution. The research findings are published in scientific journals as well as presented on the team's website. The computational tools developed from the project are incorporated into several software packages -Berkeley GW, PARATEC, and EPW- which are made freely available on the web to the research community. Another educational activity is related to public education, which is done through articles and interviews published in lay media and via public lectures by the PI and co-PI.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.