Many-Body Theory of Electronic Dynamics and Transport

技术综述：该奖项支持凝聚态物理的理论研究和教育。PI的目标是描述和建立新的多体效应，并开发能够在真实材料和设备中计算这些效应的正式工具。程序由两部分组成：(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，通常与自旋-轨道相互作用相结合，开辟控制自旋电流的新可能性的效应。例如：(I)自旋-阻力效应对一维线中自旋脉冲传输的影响，(Ii)库仑耦合双层体系中的自旋轨道和伪自旋轨道效应，(Iii)超导体中的自旋电阻和自旋霍尔效应，以及(Iv)光学产生的自旋栅弛豫和漂移。所有这些效应及其产生的系统都可以进行实验研究，使得理论和实验能够协同，从而为基于自旋的器件带来新的概念。(2)量子多体系统的电流密度泛函理论和连续介质力学。含时电流密度泛函理论(TDCDFT)允许用含时有效场统一处理实际材料中的输运和动力学问题。这一理论中的关键量是应力张量；该项目的一个主要目标是通过对其交换关联部分在单粒子轨道上的微扰展开来更好地理解量子力学应力张量。构造精确的应力张量相当于发展了量子多体系统的连续介质力学。在强关联产生高度集体行为的情况下，这样的理论可以为依赖时间的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旨在发现当电子电荷和自旋通过材料时出现的新现象。自旋是电子的一种性质，它源于量子力学，与电子的磁性有关；电子可以被认为是一块微小的磁铁。现代电子设备操纵电荷。自旋电子设备被设想为也可以操纵自旋或磁铁指向的方式。PI的研究特别集中在与自旋通过材料的传输相关的现象上，并为未来的自旋电子器件技术奠定了智力基础。PI将致力于开发新的正式理论方法，使预测真实材料的电荷和自旋输运性质成为可能。理论和实验之间的协同作用是这项工作的一个关键方面，它将最大限度地促进重大进展的前景。该项目非常适合研究生和研究生毕业后的研究人员参与，因此将有助于培养一支有科学能力的劳动力队伍。

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.