Many-Body Theory of Electronic Dynamics and Transport

该奖项支持凝聚态物理学的理论研究和教育。PI的目的是描述和建立新的多体效应，并开发正式的工具，使这些效应的计算在真实的材料和设备。本程序包括两个相关的部分：（1）自旋输运和动力学中的多体效应。将研究电子-电子相互作用的影响，通常与自旋-轨道相互作用相结合，开辟了控制自旋电流的新的可能性。例如：（i）自旋拖曳效应对自旋脉冲在一维线中传播的影响，（ii）库仑耦合双层系统中的自旋轨道和赝自旋轨道效应，（iii）超导体中的自旋电阻率和自旋霍尔效应，以及（iv）光生自旋光栅的弛豫和漂移。所有这些效应和它们发生的系统都可以通过实验研究来实现理论和实验之间的协同作用，从而产生基于自旋的器件的新概念。(2)量子多体系统的电流密度泛函理论与连续介质力学。含时电流密度泛函理论（TDCDFT）允许统一处理的输运和动力学在真实的材料的时间相关的有效字段。该理论中的关键量是应力张量;该项目的主要目标是通过单粒子轨道的交换相关部分的微扰展开来更好地理解量子力学应力张量。构造一个精确的应力张量就等于发展了量子多体系统的连续介质力学。在强相关性产生高度集体行为的情况下，这样的理论可以为依赖于时间的Kohn-Sham方程提供一个强有力的替代方案。非技术总结：该奖项支持凝聚态物理的理论研究和教育。PI旨在发现电子电荷和自旋在材料中移动时产生的新现象。自旋是电子的一种性质，它是量子力学的起源，与电子的磁性有关;电子可以被认为是一个微小的磁铁。现代电子设备操纵电荷。自旋电子器件也被设想用来操纵自旋，或者磁铁指向的方式。PI的研究特别关注与材料中自旋传输相关的现象，并为未来的自旋电子器件技术奠定了知识基础。PI将致力于开发新的正式的理论方法，使真实的材料的电荷和自旋输运性质的预测。理论和实验之间的协同互动是这项工作的一个关键方面，将最大限度地提高重大进展的前景。该项目非常适合研究生和研究人员刚刚超过他们的研究生学位，因此将有助于科学能力的劳动力。

TECHNICAL SUMMARY:This award supports theoretical research and education in condensed matter physics. The PI aims to describe and establish novel many-body effects, and to develop formal tools that would enable the calculation of these effects in real materials and devices. The program consists of two related parts:(1) Many-body effects in spin transport and dynamics. Effects will be studied in which the electron-electron interaction, often in combination with the spin-orbit interaction, opens up new possibilities of control of the spin current. Examples are: (i) the influence of the spin-drag effect on the propagation of spin pulses in one-dimensional wires, (ii) spin-orbit and pseudo-spin-orbit effects in Coulomb-coupled bilayer systems, (iii) spin resistivity and spin Hall effect in superconductors, and (iv) relaxation and drift of optically generated spin gratings. All these effects and the systems in which they occur are accessible to experimental study enabling synergy between theory and experiment that can lead to new concepts for spin-based devices.(2) Current density functional theory and continuum mechanics of quantum many-body systems. The time-dependent current density functional theory (TDCDFT) allows a unified treatment of transport and dynamics in real materials in terms of time-dependent effective fields. The key quantity in this theory is the stress tensor; a primary goal of the project is to generate a better understanding of the quantum mechanical stress tensor through a perturbative expansion of its exchange-correlation part in terms of single-particle orbitals. The construction of an accurate stress tensor is tantamount to developing a continuum mechanics for quantum many-body systems. Such a theory could offer a powerful alternative to the time-dependent Kohn-Sham equation in situations where strong correlation generates a highly collective behavior.NON-TECHNICAL SUMMARY:This award supports theoretical research and education in condensed matter physics. The PI aims to discover novel phenomena that arise when electron charge and spin move through a material. Spin is a property of an electron that is of quantum mechanical origin that is related to the magnetic properties of an electron; an electron can be thought of as a tiny magnet. Modern electronic devices manipulate charge. Spintronic devices are envisioned to also manipulate spin, or the way the magnet points. The PI's research is particularly focused on phenomena related to the transport of spin through a material and contributes to the intellectual foundations for future spintronic device technology. The PI will work to develop new formal theoretical methods that will enable predictions of the charge and spin transport properties of real materials. Synergistic interaction between theory and experiment is a key aspect of this work that will maximize prospects for significant advance. The project is well suited to involve graduate students and researchers just beyond their graduate degrees, and so will contribute to a scientifically capable workforce.