Geometric aspects of optical and transport phenomena in gapless topological phases

无间隙拓扑相中光学和传输现象的几何方面

• 批准号: 1738384
• 负责人: Dmytro Pesin
• 金额: $ 30.91万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1738384&HistoricalAwards=false
• 关键词: Geometric; aspects; optical; transport; phenomena

NONTECHNICAL SUMMARYThis award supports theoretical research and education on the interplay of geometry and topology with the quantum mechanics, and consequence for the optical and transport properties of materials. Unlike baseballs and other classical objects with motion described by trajectories, electrons in materials are described quantum mechanically by mathematical wave functions. The study of wave functions of systems of many electrons reveals distinct classes leading to a new classification of electronic phases of matter - one that goes beyond the usual classifications based, for example, on the states of aggregation, or on the existence of macroscopic order, like magnetization. These kinds of electronic phases are referred to as topologically, or more broadly, geometrically nontrivial. In this project, the PI aims to bridge the gap between the pure classification of electronic phases and the physical properties of the phases. The PI will focus on developing theory to describe the materials' optical and transport properties, for example, how well the material can conduct electricity or reflect light. The PI will investigate various optical and transport properties in chiral materials.The research is focused on topological phases in chiral materials. A chiral material has a "handedness", so it is distinct from its mirror image. Chirality may arise because of the way the atoms are arranged in the crystal, or induced by external perturbations, like electromagnetic fields, or strain. Regardless of its origin, chirality strongly affects the quantum mechanical behavior of electrons in a material, and so, its experimentally measurable and technologically relevant properties. Examples include magnetization induced by an electron current, and rotation of the plane of transmitted or reflected polarized light. This award also supports educational and training activities, aimed at improving the STEM education in the state of Utah. The primary effort will be directed at the supervision of summer research of high school physics teachers; creation of an extracurricular club for high school students, aimed at introducing its members to collaborative solving of research-type problems in physics; implementation of modern teaching techniques with particular focus on creating an inclusive environment for students from underrepresented groups. Further integration of the research and educational activities will be accomplished through supervision of graduate and undergraduate research, and establishing a journal club for graduate students.TECHNICAL SUMMARYThis award supports theoretical research and education on optical and transport properties of materials with nontrivial band geometry. The objective of this proposal is to provide theoretical insights into electrodynamic, hydrodynamic, and transport properties of disordered gapless topological phases, and to develop new theoretical approaches that would help reveal various geometric aspects of electron behavior in experiment. The research involves three main directions, integrated into an effort aimed at understanding optical and transport phenomena in gapless systems:1. Nonlocal electrodynamics and electron hydrodynamics of gapless topological phases, including the theory of chiral electron hydrodynamics and the chiral vortical effect in crystals. One focus will be on the study of the anomalous Hall effect in the hydrodynamic regime.2. Theory of nonlocal transport in disordered chiral metals. The activity will include a study of the extrinsic contributions to the dynamic chiral magnetic effect; investigation of nonperturbative instanton physics in disordered Dirac systems; development of nonlocal transport theory in nonuniform and strained topological systems.3. Nonlinear optical and magneto-optical phenomena in nonequilibrium states of Weyl and Dirac metals. The study will focus on the topological aspects of nonlinear phenomena in Weyl systems, including topological mechanisms of magneto-photovoltaic effect in Weyl semimetals, and building the theory of current-induced magneto-optical phenomena in metals with nontrivial band geometry.The research will be carried out using a wide spectrum of techniques: quantum kinetic equation for multi-band systems, field-theoretic approaches to itinerant disordered systems, numerical modelling, and ab initio studies. This award also supports educational and training activities, aimed at improving the STEM education in the state of Utah. The primary effort will be directed at the supervision of summer research of high school physics teachers; creation of an extracurricular club for high school students, aimed at introducing its members to collaborative solving of research-type problems in physics; implementation of modern teaching techniques with particular focus on creating an inclusive environment for students from underrepresented groups. Further integration of the research and educational activities will be accomplished through supervision of graduate and undergraduate research, and establishing a journal club for graduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术总结该奖项支持理论研究和教育的相互作用的几何和拓扑与量子力学，以及后果的光学和传输性能的材料。与棒球和其他经典物体的运动轨迹不同，材料中的电子是用数学波函数量子力学描述的。对多电子系统的波函数的研究揭示了不同的类别，从而导致了物质电子相的新分类--一种超越了通常基于聚集态或宏观有序存在（如磁化）的分类。这些种类的电子相被称为拓扑，或更广泛地说，几何非平凡的。在这个项目中，PI旨在弥合电子相的纯分类和相的物理性质之间的差距。PI将专注于开发理论来描述材料的光学和传输特性，例如，材料可以导电或反射光。该专业主要研究手性材料的光学和输运性质，主要研究手性材料的拓扑相。手征材料具有“手性”，因此它与其镜像不同。手征性可能是由于原子在晶体中的排列方式而产生的，或者是由外部扰动（如电磁场或应变）引起的。无论其起源如何，手性强烈影响材料中电子的量子力学行为，因此，它的实验可测量和技术相关属性。例子包括由电子流引起的磁化，以及透射或反射的偏振光平面的旋转。该奖项还支持教育和培训活动，旨在改善犹他州的STEM教育。主要工作将是监督高中物理教师的暑期研究;为高中学生创建一个课外俱乐部，旨在向其成员介绍合作解决物理研究型问题;采用现代教学技术，特别侧重于为代表性不足的群体的学生创造一个包容性环境。研究和教育活动的进一步整合将通过研究生和本科生研究的监督，并建立一个研究生期刊俱乐部来完成。技术总结这个奖项支持理论研究和教育的光学和传输性质的材料与非平凡的能带几何。这个建议的目的是提供理论上的见解电动力学，流体动力学和输运性质的无序无间隙拓扑相位，并开发新的理论方法，这将有助于揭示各种几何方面的电子行为在实验中。该研究涉及三个主要方向，整合到一个努力，旨在了解光学和传输现象的无隙系统：1。无带隙拓扑相的非定域电动力学和电子流体力学，包括手征电子流体力学和晶体中手征涡旋效应。其中一个重点将是在流体力学制度的反常霍尔效应的研究。无序手性金属的非定域输运理论。活动将包括研究非本征对动态手征磁效应的贡献;研究无序狄拉克系统中的非微扰瞬子物理;发展非均匀和应变拓扑系统中的非局域输运理论。外尔和狄拉克金属非平衡态中的非线性光学和磁光现象。 本研究将集中于Weyl系统中非线性现象的拓扑方面，包括Weyl半金属中磁光伏效应的拓扑机制，以及建立具有非平凡能带几何的金属中电流诱导磁光现象的理论。研究将使用广泛的技术进行：多带系统的量子动力学方程、流动无序系统的场论方法、数值建模和从头算研究。该奖项还支持教育和培训活动，旨在改善犹他州的STEM教育。主要工作将是监督高中物理教师的暑期研究;为高中学生创建一个课外俱乐部，旨在向其成员介绍合作解决物理研究型问题;采用现代教学技术，特别侧重于为代表性不足的群体的学生创造一个包容性环境。研究和教育活动的进一步整合将通过研究生和本科生研究的监督，并为研究生建立一个期刊俱乐部来实现。这个奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。