Theoretical Solid State Physics

该补助金支持凝聚态物理和计算材料科学的长期，广泛的理论研究计划。 研究项目涵盖半导体、金属、表面和界面、缺陷、超导性、压力下的材料、团簇、富勒烯基材料、纳米管和其他纳米结构、共轭聚合物以及固体中的多电子效应等领域。 主要目的是利用量子理论来解释和预测材料的性质。 重点放在使用现实的模型，密切合作，与实验，调查和建议，生产新的和有用的材料，发展新的理论方法，并预测有关的电子和结构性质的固体。许多新的技术，基于量子理论的发展，在这个研究计划，使精确计算的真实的材料。 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-Saltpeter方程的光激发。 其他研究依赖于变分和扩散蒙特卡罗方法，分子动力学模拟，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。过去的成功包括精确的预测性能和新材料的存在，电子结构计算，允许带隙工程方法的技术，和新的理论方法。 该研究计划建立在这项工作的基础上，并朝着几个新的方向发展。 具体项目包括与理解和预测纳米管、富勒烯、分子结和其他纳米结构的性质有关的项目;材料在环境压力和高压下的电子、振动和结构性质;固体的机械性质、弹性稳定性和强度极限;固体、缺陷和聚合物的电子空穴相互作用和光学性质;准粒子激发和电子相关性;超导性和新的形式主义。 研究生和博士后研究员广泛参与这项研究。%该补助金支持凝聚态物理和计算材料科学的长期，广泛的理论研究计划。 研究项目涵盖半导体、金属、表面和界面、缺陷、超导性、压力下的材料、团簇、富勒烯基材料、纳米管和其他纳米结构、共轭聚合物以及固体中的多电子效应等领域。 主要目的是利用量子理论来解释和预测材料的性质。 重点放在使用现实的模型，与实验，调查和生产新的和有用的材料，新的理论方法的发展，并预测有关的电子和固体结构特性的建议密切合作。 研究生和博士后研究员广泛参与这项研究。

This grant supports a long-range, broad-based theoretical research program in condensed matter physics and computational materials science. The research projects cover the fields of semiconductors, metals, surfaces and interfaces, defects, superconductivity, materials under pressure, clusters, fullerene-based materials, nanotubes and other nanostructures, conjugated polymers, and many-electron effects in solids. The major objective is to use quantum theory to explain and predict the properties of materials. Emphasis is placed on using realistic models, close collaboration with experimentalists, investigations and suggestions for producing novel and useful materials, development of new theoretical approaches, and predictions related to electronic and structural properties of solids.Many new techniques based on quantum theory were developed in this research program to enable accurate calculations of 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-Saltpeter equation for optical excitations. Other studies rely on variational and diffusion Monte Carlo approaches, molecular dynamics simulations, dielectric function methods, BCS theory, density functional perturbation theory, and extensions of standard many-body theory.Past successes include accurate predictions of properties and the existence of new materials, electronic structure calculations which allow band-gap engineering approaches to technology, and new theoretical approaches. The research program builds on this work and goes in several new directions. Specific projects include those related to understanding and predicting the properties of nanotubes, fullerenes, molecular junctions, and other nanostructures; electronic, vibrational and structural properties of materials at ambient and high pressure; mechanical properties, elastic stability and limit of strength of solids; electron-hole interaction and optical properties of solids, defects and polymers; quasiparticle excitations and electron correlations; and superconductivity and new formalisms. There is extensive involvement of graduate students and postdoctoral associates in this research.%%%This grant supports a long-range, broad-based theoretical research program in condensed matter physics and computational materials science. The research projects cover the fields of semiconductors, metals, surfaces and interfaces, defects, superconductivity, materials under pressure, clusters, fullerene-based materials, nanotubes and other nanostructures, conjugated polymers, and many-electron effects in solids. The major objective is to use quantum theory to explain and predict the properties of materials. Emphasis is placed on using realistic models, close collaboration with experimentalists, investigations and suggestions for producing novel and useful materials, development of new theoretical approaches, and predictions related to electronic and structural properties of solids. There is extensive involvement of graduate students and postdoctoral associates in this research.***