Theoretical Solid State Physics

技术概述：该奖项支持凝聚态物理和计算材料科学的理论研究和教育。这些项目涵盖了一系列的主题，包括石墨烯、纳米管、半导体、金属、界面、超导、磁性系统和分子结的研究。主要目的是解释和预测材料的性质。这些领域使用先前开发的和正在进行的基于量子理论的理论和计算技术的增强来解决。这些技术使对真实材料的精确计算成为可能。特别是，在密度泛函形式中应用从头算伪势方法和总能量技术来计算基态性质。利用基于GW近似的准粒子激发第一性原理自能方法和基于Bethe-Salpter方程的双粒子格林函数方法研究了光激发的激发态（光谱）现象。其他研究依赖于分子动力学和蒙特卡罗模拟、介电函数方法、BCS理论、密度泛函微扰理论和标准多体理论的扩展。对现有的处理电子相关的方法进行了扩充，并采用了局域化方法。与各实验小组的密切合作是这项研究活动的重要组成部分。过去的成功包括对性能的准确预测和新材料的存在，包括纳米结构，以及允许带隙工程技术方法的电子结构计算。目前的努力扩展了现有的研究，并增加了几个与理解和预测石墨烯系统、纳米管和相关纳米结构的性质有关的项目；半导体、金属和新材料的电子和结构特性；准粒子激发、激子效应和材料与降维系统的光学响应通过分子和纳米级结的电子传递；超导、电子-声子相互作用及相关现象。这项研究虽然是基础的，但它支持了先进材料的进一步发展，特别是那些与半导体技术和纳米科学相关的材料。这一努力的更广泛影响包括研究生和博士后研究人员的教育和专业培训，以及许多物理和化学研究人员和工程师可以使用的计算机代码的开发。非技术总结：该奖项支持凝聚态物理和计算材料科学的理论研究和教育。这些项目涵盖了广泛的主题，包括高性能材料和纳米科学领域。这项研究将有助于基于量子理论的理论和计算技术的发展，以实现对测量性质的精确计算，以及对以前没有在实验室中创建的新材料的特征和存在的预测。这些技术具有很高的可靠性，因为计算是基于从物理学基本原理发展而来的理论。具体项目包括那些与理解和预测诸如石墨烯（一种二维单层碳）、纳米结构（比人类头发小10万倍的结构）和半导体等特殊材料的特性有关的项目，这些材料对技术至关重要。感兴趣的特性包括与材料如何与光相互作用（如吸收和发射），材料强度和电性能相关的特性，仅举几例。该项目非常适合研究生和刚刚超过研究生学位的研究人员，因此，它将对科学能力劳动力的教育和培训做出重大贡献。理论工作与实验研究直接相关，导致基础科学和应用科学上频繁的实验-理论合作。

TECHNICAL SUMMARY:This award supports theoretical research and education in condensed matter physics and computational materials science. The projects cover a range of topics including studies of graphene, nanotubes, semiconductors, metals, interfaces, superconductivity, magnetic systems, and molecular junctions. The major objective is to explain and predict the properties of materials. These areas are addressed using previously developed and ongoing enhancements to theoretical and computational techniques based on quantum theory. These techniques enable accurate calculations for real materials. In particular, the ab initio pseudopotential method and total energy techniques are applied within the density functional formalism 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-Salpter equation for optical excitations. Other studies rely on molecular dynamics and Monte Carlo simulations, dielectric function methods, BCS theory, density functional perturbation theory, and extensions of standard many-body theory. Augmentation of existing methods to deal with electron correlations and localized methods are also employed. Close collaborations with various experimental groups are an essential component of this research activity. Past successes include accurate predictions of properties and the existence of new materials including nanostructures, and electronic structure calculations which allow band gap engineering approaches for technology. The present effort extends existing research and adds several projects related to understanding and predicting the properties of graphene systems, nanotubes, and related nanostructures; electronic and structural properties of semiconductors, metals, and novel materials; quasiparticle excitations, excitonic effects, and optical responses of materials and reduced-dimensional systems; electron transport through molecular and nanoscaled junctions; superconductivity, electron-phonon interactions, and related phenomena. The research, though basic, supports further development of advanced materials, especially those relevant to semiconductor technology and nanoscience. The broader impacts of the effort include the education and professional training of graduate students and postdoctoral researchers, as well as the development of computer codes that can be used by many physics and chemistry researchers and by engineers for applications. NON-TECHNICAL SUMMARY:This award supports theoretical research and education in condensed matter physics and computational materials science. The projects cover a broad range of topics including the fields of high performance materials and nanoscience. The research will contribute to the development of theoretical and computational techniques based on quantum theory to enable accurate calculations of measured properties as well as the prediction of the characteristics and the existence of new materials that were not previously created in the laboratory. These techniques have high reliability because the computations are based on theory developed from basic principles of physics. Specific projects include those related to understanding and predicting the properties of exotic materials such as graphene (a two-dimensional, single layer of carbon) and nanostructures (structures that are some 100,000 times smaller than the human hair) and semiconductors important for technology. The properties of interest include characteristics related to how materials interact with light (such as absorption and emission), material strength, and electrical properties, to name a few. The project is well suited for involving graduate students and researchers just beyond their graduate degrees, hence, it will significantly contribute to the education and training of a scientifically capable workforce. The theoretical work bears directly on experimental studies resulting in frequent experimental-theoretical collaborations on basic and applied science.