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

实验技术的最新进展为在二维电子系统中前所未有地精确研究电荷和自旋动力学开辟了道路，二维电子系统形成于半导体、金属和金属氧化物之间的界面以及各种层状材料中。 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新技术发展的有希望的候选者。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，自旋和能量传输有关的关键问题。将被研究的特定系统包括诸如单原子厚形式的碳（称为石墨烯）和由过渡金属原子和硫组成的其他石墨烯状二维材料等材料。 通过仔细的分析和计算研究，PI将研究这些系统中自旋和电荷自由度之间的相互作用，并预测外部场如何影响系统的稳定性。（例如电，热）可以被操纵，以产生新的现象，可能导致技术创新。这个项目的战略定位在基础凝聚态理论，应用物理学和计算材料科学之间的接口，并且在电子和热能传输中具有潜在的技术意义。在博士后研究人员和外部合作者的协助下开展这项研究的同时，PI将每周举办一次关于“凝聚态理论选定主题”的研讨会，向密苏里州大学物理系的研究生介绍该项目执行的基本概念和方法。该研究的更广泛的意义将通过PI提供的公开讲座向更广泛的观众解释。技术总结实验技术的最新进展，如瞬态光栅光谱学，磁偏振测量学，自旋噪声光谱学和自旋电流的非线性光学产生开辟了前所未有的准确研究二维电子液体中的电荷和自旋动力学的道路，其存在于半导体、金属和金属氧化物之间的界面处，以及存在于诸如石墨烯、MoS 2的层状材料和拓扑绝缘体的表面中。 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信息处理和能量转换领域新技术发展的有希望的候选者。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，自旋和能量传输有关的关键问题。计划活动的核心是一系列基本物理问题，这些问题将在三年内并行或顺序解决。这些是：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的磁场;2.发展石墨烯和类石墨烯材料中的自旋扩散、热导率和粘度的理论，直到计算显示出无碰撞（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相互作用电子的新热电现象;4.发展具有强自旋-轨道相互作用的金属和氧化物界面的自旋霍尔效应和自旋-电流效应理论。该项目处于基础凝聚态理论、应用物理和计算材料科学之间的战略位置，并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协助下开展这项研究的同时，PI将每周举办一次关于“凝聚态理论选定主题”的研讨会，向密苏里州大学物理系的研究生介绍该项目执行的基本概念和方法。研究的更广泛意义将通过PI提供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.