CAREER: First-Principles Electron and Spin Dynamics in Materials with Spin-Orbit Coupling

该职业奖支持研究和教育发展计算方法，以调查和理解材料中电子的详细运动。这项研究的重点是电子的一种被称为自旋的特性，它类似于行星绕其轴旋转。在含有重原子的材料中，如铋或钨等，电子的自旋和空间运动是耦合的；这种所谓的自旋轨道耦合是最近材料物理学突破的核心。研究的目的是发展精确的方法来计算材料中电子的动力学，其中自旋轨道耦合是重要的。传统研究通常采用简单的模型来解释实验，与之相反，该研究的目标是开发真正的预测计算，不受经验参数的影响，可以广泛应用于新材料。通过精确计算电子与原子振动的相互作用以及材料晶体结构中的缺陷，该项目将对新技术尚未开发潜力的材料进行微观理解，包括新型金属和含有重原子的超薄半导体。这项工作将产生在电子、可再生能源、光谱学、计算和量子技术方面取得突破性进展所需的知识和计算方法。这些努力对于确立美国在基于新材料的新兴技术领域的领导地位至关重要。项目中生成的计算方法将免费提供，用户友好，并广泛使用；用户将包括学术研究团体、国家实验室和工业界。该项目旨在为参与其中的高中生、本科生和研究生提供丰富的机会。PI将通过参与活动对高中生进行科学计算方面的培训。研究团队将接待本科生，他们将通过学习前沿的计算材料物理学来为研究和开发课程做出贡献。该项目将有助于培养在物理、计算机科学和材料科学交叉领域具有独特跨学科背景的研究生。他们将具备领导美国计算物理和材料科学研究的能力。该职业奖支持研究和教育，以发展对自旋-轨道耦合材料中载流子及其自旋动力学的详细理解。该项目将开发新的理论和计算方法，以准确计算具有自旋-轨道耦合的材料中电子和自旋的散射、弛豫、输运和超快动力学的时间尺度和机制。虽然电荷和自旋动力学的计算通常是启发式的，但PI将基于密度泛函理论和相关方法开发预测的第一性原理计算，这些方法不受经验参数的影响，可以广泛应用于新材料。通过精确计算电子和自旋与晶格振动和晶体缺陷的相互作用，该项目将对材料进行微观理解，但尚未开发新技术的潜力。研究团队将专注于一系列具有自旋轨道耦合的材料，包括用于新型光电器件的二维过渡金属二硫族化合物，用于高效太阳能电池的卤化铅钙钛矿，以及用于新基础物理的拓扑半导体和半金属。这些材料中复杂的原子结构强调需要精确和广泛适用的方法来计算材料中的载流子和自旋动力学。项目中产生的新方法和代码将包含在由PI开发的PERTURBO软件中，该软件旨在促进对材料中电子和激发态动力学的理解。这里所追求的第一性原理方法可以广泛应用于电子和自旋器件，以及推进超快电子和自旋光谱。这些努力对于确立美国在新兴电子、可再生能源、计算和量子技术方面的领导地位至关重要。该项目通过培训新一代的高中生和本科生科学计算，将研究和教育结合起来。从事该项目的研究生将在物理学、计算机科学和材料科学的交叉领域获得独特的跨学科背景。他们将具备领导美国计算物理和材料科学研究的能力。

NONTECHNICAL SUMMARYThis CAREER award supports research and education in developing computational methodology for investigating and understanding in detail the motion of electrons in materials. The focus of the research is on a property of electrons called spin, which is analogous to the spinning rotation of a planet around its axis. In materials containing heavy atoms, such as bismuth or tungsten among others, the spin and spatial motions of electrons are coupled; this so-called spin-orbit coupling is at the center of recent breakthroughs in materials physics. The objective of the research is to develop accurate methodology for the calculation of the dynamics of electrons in materials where spin-orbit coupling is significant. In contrast to conventional studies, which typically employ simple models to interpret experiments, the goal is to develop truly predictive calculations that are free of empirical parameters and can be applied broadly to new materials. By accurately computing the interactions of electrons with atomic vibrations and defects in the crystal structure of the material, the project will develop a microscopic understanding of materials with yet untapped potential for new technology, including novel metals and ultrathin semiconductors containing heavy atoms. The work will generate knowledge and computational methods needed for breakthrough advances in electronics, renewable energy, spectroscopy, computing, and quantum technology. These efforts are critical for establishing a United States leadership in emerging technologies based on novel materials. The computational methods generated in the project will be freely available, user-friendly, and widely usable; users will include academic research groups, national laboratories, and the industry. This project aims to be an enriching opportunity for the high-school, undergraduate, and graduate students involved. The PI will train high-school students on scientific computing through engaging activities. The research team will host undergraduate students, who will contribute to research and develop their curricula by learning cutting-edge computational materials physics. The project will contribute to the development of graduate students with a unique interdisciplinary background at the intersection of physics, computer science, and materials science. They will be equipped to lead computational physics and materials science research in the United States. TECHNICAL SUMMARYThis CAREER award supports research and education in developing a detailed understanding of the dynamics of charge carriers and their spin in materials with spin-orbit coupling. The project will develop new theory and computational methods to accurately calculate the timescale and mechanisms of scattering, relaxation, transport, and ultrafast dynamics of electrons and spin in materials with spin-orbit coupling. While computations of charge and spin dynamics are typically heuristic, the PI will develop predictive first-principles calculations based on density functional theory and related methods that are free of empirical parameters and can be applied broadly to new materials. By accurately computing the interactions of electrons and spin with lattice vibrations and crystallographic defects, the project will develop a microscopic understanding of materials with yet untapped potential for new technology. The research team will focus on a range of materials with spin-orbit coupling, including two-dimensional transition-metal dichalcogenides for novel optoelectronic devices, lead-halide perovskites for efficient solar cells, and topological semiconductors and semimetals for new fundamentals physics. The complex atomic structure in these materials underscores the need for accurate and broadly applicable methods to compute carrier and spin dynamics in materials. The new methods and code generated in the project will be included in PERTURBO, a software developed by the PI to advance understanding of electron and excited-state dynamics in materials. The first-principles approach pursued here can be applied broadly to electronic and spin-based devices, as well as to advancing ultrafast electron and spin spectroscopies. These efforts are critical for establishing a United States leadership in emerging electronic, renewable energy, computing, and quantum technologies. The project integrates research and education by training a new generation of high-school and undergraduate students in scientific computing. The graduate students working on the project will acquire a unique interdisciplinary background at the intersection of physics, computer science, and materials science. They will be equipped to lead computational physics and materials science research in the United States.