Spin, Charge, and Energy Transport in Semiconductor Nanostructures and Graphene-Like Materials

最近实验技术的进步为在二维电子系统中对电荷和自旋动力学进行前所未有的精确研究开辟了道路。二维电子系统形成于半导体、金属、金属氧化物和各种层状材料之间的界面。这些材料以有效和可控的方式传输自旋、电荷和能量的能力，使它们成为信息处理和能量转换领域发展新技术的有希望的候选者。该项目结合了理论研究和伴随的教育和推广活动，解决与单层和多层电子系统中的电荷、自旋和能量输运有关的关键问题。将被研究的特殊系统包括单原子厚度形式的碳，称为石墨烯，以及其他由过渡金属原子和硫组成的石墨烯类二维材料。通过仔细的分析和计算研究，PI将检查这些系统中自旋自由度和电荷自由度之间的相互作用，并预测如何操纵外部场（例如电，热）以产生可能导致技术创新的新现象。该项目战略性地定位于基础凝聚态理论、应用物理和计算材料科学的交叉点，在电子学和热能传输方面具有潜在的技术意义。在博士后研究人员和外部合作者的帮助下开展这项研究的同时，PI将每周举办一次关于“凝聚态理论选题”的研讨会，向密苏里大学物理系的研究生介绍项目执行的基本概念和方法。该研究的广泛意义将通过PI的公开讲座向更广泛的受众解释。技术综述：实验技术的最新进展，如瞬态光栅光谱、磁极化法、自旋噪声光谱和自旋电流的非线性光学产生，为前所未有地精确研究二维电子液体中的电荷和自旋动力学开辟了道路，这些电子液体存在于半导体、金属和金属氧化物之间的界面，以及石墨烯、MoS2等层状材料和拓扑绝缘体表面。这些系统以有效和可控的方式传输自旋、电荷和能量的能力使它们成为发展新技术的有希望的候选者，无论是在信息处理领域还是在能量转换领域。该项目结合理论研究和伴随的教育和推广活动，解决与单层和多层电子系统中的电荷、自旋和能量输运有关的关键问题。预计活动的核心是一组基本物理问题，这些问题将在三年的时间内并行或依次解决。这些都是:1。评估石墨烯和类石墨烯材料中二维电子液体的微观自旋-电荷响应函数，包括电子-电子相互作用、无序、自旋-轨道耦合和适当近似下的磁场；2 .发展石墨烯和类石墨烯材料的自旋扩散、导热性和粘度理论，使计算显示出无碰撞（高频）和碰撞主导（流体动力学）制度之间的交叉；3 .识别和量化多层结构中电子相互作用的新型热电现象；发展了具有强自旋轨道相互作用的金属和氧化物界面上的自旋霍尔效应和自旋电效应理论。该项目战略性地定位于基础凝聚态理论、应用物理和计算材料科学的交叉点，在电子学和热能传输方面具有潜在的技术意义。在博士后研究人员和外部合作者的帮助下开展这项研究的同时，PI将每周举办一次关于“凝聚态理论选题”的研讨会，向密苏里大学物理系的研究生介绍项目执行的基本概念和方法。该研究的广泛意义将通过PI的公开讲座向更广泛的受众解释。

NON-TECHNICAL SUMMARYRecent advances in experimental techniques have opened the way to unprecedentedly accurate studies of charge and spin dynamics in two-dimensional electronic systems, which are formed at the interface between semiconductors, metals, and metal oxides, and in various layered materials. The ability of these materials to transport spin, charge and energy in an efficient and controllable manner makes them promising candidates for the development of new technologies, both in the field of information processing and in that of energy conversion. This project combines theoretical research and accompanying educational and outreach activities that address key issues relating to charge, spin, and energy transport in single- and multi-layered electronic systems. Particular systems which will be investigated include materials such a single-atom-thick form of carbon, known as graphene, and other graphene-like two-dimensional materials composed of transition metal atoms and sulfur. Through careful analytical and computational studies, the PI will examine the interplay between the spin and charge degrees of freedom in these systems, and predict how external fields (e.g. electric, thermal) can be manipulated to bring out novel phenomena that could lead to technological innovations.This project is strategically positioned at the interface between fundamental condensed matter theory, applied physics, and computational materials science, and has potential technological implications in electronics and thermal energy transport. While carrying out this research with the assistance of postdoctoral researchers and external collaborators, the PI will maintain a weekly seminar on "Selected topics in condensed matter theory", in which the graduate students of the Physics Department at the University of Missouri will be introduced to the basic concepts and methods which underlie the execution of the project. The broader significance of the research will be explained to a wider audience through public lectures delivered by the PI.TECHNICAL SUMMARYRecent advances in experimental techniques such as transient grating spectroscopy, magnetopolarimetry, spin noise spectroscopy, and nonlinear optical generation of spin currents open the way to unprecedentedly accurate studies of charge and spin dynamics in two-dimensional electron liquids, which exist at the interfaces between semiconductors, metals, and metal oxides, and in layered materials such as graphene, MoS2, and the surface of topological insulators. The ability of these systems to transport spin, charge and energy in an efficient and controllable manner makes them promising candidates for the development of new technologies, both in the field of information processing and that of energy conversion. This project combines theoretical research and accompanying educational and outreach activities addressing key issues relating to charge, spin, and energy transport in single- and multi-layered electronic systems. At the core of the projected activity lies a set of basic physics problems which will be addressed in parallel or sequentially during a period of three years. These are:1. Evaluating the microscopic spin-charge response functions for two-dimensional electron liquids in graphene and graphene-like materials, including electron-electron interactions, disorder, spin-orbit couplings, and magnetic fields in suitable approximations;2. Developing the theory of spin diffusion, thermal conductivity, and viscosity in graphene and graphene-like materials, to the point where the calculations exhibit the crossover between the collisionless (high-frequency) and collision-dominated (hydrodynamic) regimes;3. Identifying and quantifying novel thermoelectric phenomena for interacting electrons in multi-layer structures;4. Developing the theory of spin Hall effect and spin-galvanic effects at metallic and oxide interfaces with strong spin-orbit interactions.This project is strategically positioned at the interface between fundamental condensed matter theory, applied physics, and computational materials science, and has potential technological implications in electronics and thermal energy transport. While carrying out this research with the assistance of postdoctoral researchers and external collaborators, the PI will maintain a weekly seminar on "Selected topics in condensed matter theory", in which the graduate students of the Physics Department at the University of Missouri will be introduced to the basic concepts and methods which underlie the execution of the project. The broader significance of the research will be explained to a wider audience through public lectures delivered by the PI.