Theoretical Solid State Physics

非技术概述该奖项支持理论和计算研究和教育，以便在微观层面上理解材料和纳米结构的电子、光学和磁性。凝聚态物质的迷人性质和现象源于构成这种物质的电子和离子的相互作用，其中许多离子是现代技术的核心，如电子学、光电子学、光伏和其他能量转换设备。通过改变化学成分或沿一个或多个维度将材料限制在纳米尺度上，这些性质往往会发生显着变化或出现新的现象。这个项目的中心是使用量子理论、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)计算机的可用性使该团队能够获得原子薄(沿着一维或多维)材料、纳米结构、界面和缺陷现象、新型超导体和光催化材料的行为的第一性原理(即没有经验参数)的解释和预测。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。研究成果发表在科学期刊上，并在该团队的网站上公布。从该项目开发的计算工具被合并到几个软件包中，这些软件包可在网上免费向研究界提供。另一项教育活动是与公众教育有关的，这是通过在非专业媒体上发表的文章和采访，以及PI和共同PI的公开讲座来完成的。技术概述该奖项支持通过执行第一原理量子计算在微观水平上理解材料和纳米结构的电子、运输、光学和磁性的理论和计算研究和教育。研究的主题包括：i)原子薄的一维和二维系统的结构和动力学性质；ii)降维系统和块体材料中的新的光学、拓扑和磁性性质；以及iii)电子-声子相互作用、超导电性和相关现象。主要目标是使用多体量子理论和新概念，如拓扑学中的概念来解释和预测真实材料的性质，特别是对于低维系统。重点放在现实的模型，与实验者的密切合作，为生产新的和有用的材料而进行的调查和建议，新的理论和计算方法的发展，以及与结构、电子、磁、超导、运输和光学性质有关的预测。基于多体量子理论的最新技术被用来实现对真实材料的准确的第一原理计算。特别是，在密度泛函形式(DFT)中应用从头算赝势方法和总能量技术来计算基态性质。用基于准粒子激发的GW近似的第一原理自能方法和基于光激发的Bethe-Salpeter方程的从头算双粒子格林函数方法研究了激发态(光谱)现象。对磁性行为和电子-声子耦合现象的研究，超出了目前的技术水平，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。第一原理计算在适当的情况下用模型哈密顿研究进行补充，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)和博士后研究员在当前的量子技术革命中使用材料进行研究和开发。研究成果发表在科学期刊上，并在该团队的网站上公布。从该项目开发的计算工具被整合到几个软件包中--Berkeley GW、PARATEC和EPW--这些软件包可以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，这是通过在非专业媒体上发表文章和采访，以及通过PI和共同PI的公开演讲来完成的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.