Dynamical Properties of Nanoscale Systems

技术概述：该奖项支持有关纳米系统动力学性质的理论研究和教育。研究人员正在研究以前未探索过的有关纳米系统中传输的基本问题和新现象。目前正在努力开发新的方法和理论来描述它们，将第一原理方法和模型计算结合起来，并提出可以用现有实验能力检验的预测。这项研究的试验台系统包括(但不限于)原子和分子结，即由相对较少的原子连接到更大的(大块)电极上的结构。研究人员将确定初始相关性和记忆效应对纳米结构传输特性的作用。它还用来确定在什么条件下，电子流会形成湍流液体的特征。在给定一组初始条件的情况下，研究人员将从理论上研究这些系统中电子动力学的空间和时间关联规律。实际上，有必要知道上述性质如何依赖于i)电子液体的参数，如其密度和粘度，ii)结的电阻，以及iii)其原子几何和结构。最后，最大的问题是确定使用含时密度泛函方法的电导的动力学计算是否能够用可用的泛函来捕捉多体效应，如库仑阻塞。在这个理论背景下，研究人员计划研究自旋输运中的新的多体效应和概念。所考虑的第一个效应与电子液体的粘性有关，并引起动态自旋阻力。第二个原因是局域电阻自旋偶极子之间的相互作用，即由于结处电子的散射而产生的局域自旋偶极子。这些效应肯定会导致磁阻，在某些条件下甚至可能是纳米结构中自旋输运的主要贡献。上述研究将结合含时密度泛函理论和分析模型进行。这些预测可以用现有的实验能力直接检验。除了基础研究外，这些调查还具有实际和教育意义。人们一直在努力将理论预测与实验验证的数量联系起来。这一努力有助于培养研究生和本科生，他过去的记录证明了这一点。以上所有项目都特别适合博士论文。它们涉及数值和分析工作的平衡组合，以及许多新的物理概念。这为攻读博士学位的高级学生提供了强有力的教育体验。该计划的某些方面也适用于本科生的研究，使在大学学习科学的学生有机会体验理论研究并获得相关的经验和教育。这项研究对纳米系统组成的电路的运行具有实际意义。因此，通过该项目获得的实际见解将为该领域未来的发展产生基本知识和重要的新投入。将研究和教育整合在像目前这样具有挑战性的计划中，将有助于培养在学术界和工业领域都需要专业知识的高技能人才。非技术摘要：该奖项支持纳米系统中导电动力学特性的理论研究和教育。研究人员正在研究以前未探索过的有关纳米系统中传输的基本问题和新现象。目前正在努力开发新的方法和理论来描述它们，将基本理论方法和模型计算结合起来，并提出可以用现有实验能力检验的预测。本研究的试验台系统包括(但不限于)原子和分子结，即由相对较少的原子连接到更大的(大块)电极上的结构。除了基础研究，该研究还具有实际和教育意义。人们一直在努力将理论预测与实验验证的数量联系起来。这一努力对研究生和本科生的培训做出了贡献，他过去的记录证明了这一点。以上所有项目都特别适合博士论文。它们涉及数值和分析工作的平衡组合，以及许多新的物理概念，这为攻读博士学位的高级学生提供了强有力的教育体验。该计划的某些方面也适用于本科生的研究，使在大学学习科学的学生有机会体验理论研究并获得相关的经验和教育。这项研究对纳米系统组成的电路的运行具有实际意义。因此，通过该项目获得的实际见解将为该领域未来的发展产生基本知识和重要的新投入。将研究和教育整合到像目前这样具有挑战性的项目中，将有助于培养具有学术界和工业界高需求领域专业知识的高技能人才。

TECHNICAL SUMMARY:This award supports theoretical research and education into dynamical properties of nanoscale systems. Researchers are investigating previously unexplored fundamental issues and novel phenomena concerning transport in nanoscale systems. Efforts are in developing novel approaches and theories to describe them, by combining first-principles methods and model calculations, and advancing predictions which can be tested with available experimental capabilities. Test bed systems for this research include (but are not limited to) atomic and molecular junctions, i.e., structures made of a relatively small number of atoms connected to much larger (bulk) electrodes.New research investigations are initiated in this work. Researchers will determine what the role of initial correlations and memory effects is on the transport properties of nanostructures. It is also intended to determine under which conditions the electron flow develops characteristics of a turbulent liquid. Researcher will theoretically investigate, for given a set of initial conditions, the spatial and temporal correlation laws of the electron dynamics in these systems. Practically, it is necessary to know how the above properties depend on i) the parameters of the electron liquid, such as its density and viscosity, ii) the resistance of the junction, and iii) its atomic geometry and structure. Finally, the grand question, is to determine whether a dynamical calculation of conductance, using time-dependent density-functional methods, is able to capture many-body effects, such as coulomb blockade, with available functionals.In this theoretical setting, the researcher plans to investigate novel many-body effects and concepts in spin transport. The first effect considered is related to the viscous nature of the electron liquid and gives rise to a dynamical spin resistance. The second one is due to the interaction between local resistivity spin dipoles, i.e., dipoles of local spin due to the scattering of electrons at the junction. These effects definitely contribute to magnetoresistance, and under certain conditions may even be the dominant contributions to spin transport in nanostructures. The above studies will be carried out using a combination of Time-Dependent Density-Functional Theory and analytical models. Predictions will be made which can be directly tested with available experimental capabilities.Beyond basic research, the investigations have practical and education consequences. There is a continuing effort to connect theoretical predictions with quantities that are verified experimentally. The effort contributes to the training of both graduate and undergraduate students as demonstrated by his past track record. All of the above projects are particularly suitable for a Ph.D. thesis. They involve a balanced combination of numerical and analytical work, as well a lot of novel physical concepts. This provides a robust educational experience for the advanced students studying for the doctorate. Selected aspects of the program are also amenable to undergraduate research giving the student studying science in college an opportunity to experience theoretical research and gain the associated experience and education. The research has practical implications in the operation of electrical circuits made of nanoscale systems. The physical insights obtained with this project will therefore generate basic knowledge and significant new input for future developments in the field. The integration of research and education within a challenging program like the present one will aid the preparation of highly skilled personnel with expertise in an area of high demand both in academia and in industry.NONTECHNICAL SUMMARY:This award supports theoretical research and education into dynamical properties of electrical conduction in nanoscale systems. Researchers are investigating previously unexplored fundamental issues and novel phenomena concerning transport in nanoscale systems. Efforts are in developing novel approaches and theories to describe them, by combining fundamental theoretical methods and model calculations, and advancing predictions which can be tested with available experimental capabilities. Test bed systems for this research include (but are not limited to) atomic and molecular junctions, i.e., structures made of a relatively small number of atoms connected to much larger (bulk) electrodes.Beyond basic research, the investigations have practical and education consequences. There is a continuing effort to connect theoretical predictions with quantities that are verified experimentally. The effort contributed to the training of both graduate and undergraduate students as demonstrated by his past track record. All of the above projects are particularly suitable for a Ph.D. thesis. They involve a balanced combination of numerical and analytical work, as well a lot of novel physical concepts this providing a robust educational experience for the advanced students studying for the doctorate. Selected aspects of the program are also amenable to undergraduate research giving the student studying science in college an opportunity to experience theoretical research and gain the associated experience and education. The research has practical implications in the operation of electrical circuits made of nanoscale systems. The physical insights obtained with this project will therefore generate basic knowledge and significant new input for future developments in the field. The integration of research and education within a challenging program like the present one will aid the preparation of highly skilled personnel with expertise in an area of high demand both in academia and in industry.