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几何学和拓扑学与量子力学相互作用的理论研究和教育，以及材料的光学和传输性质的结果。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来描述的。对多电子系统波函数的研究揭示了导致物质电子相新分类的不同类别--这种分类超越了通常的分类，例如，基于聚集状态，或基于宏观秩序的存在，如磁化。这些类型的电子相在拓扑学上，或者更广泛地说，在几何上是非平凡的。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将专注于开发描述材料的光学和传输性质的理论，例如，材料的导电性或反射性有多好。PI将研究手性材料的各种光学和输运性质，研究的重点是手性材料中的拓扑相。手性材料有一种“利手”，因此它有别于它的镜像。手性可能是由于原子在晶体中的排列方式引起的，也可能是由外部扰动(如电磁场或应变)引起的。不管它的起源如何，手性强烈地影响着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的性质。例如，由电子电流引起的磁化，以及透射式或反射式偏振光平面的旋转。该奖项还支持旨在改善犹他州STEM教育的教育和培训活动。主要工作将针对监督高中物理教师的暑期研究；为高中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性问题；实施现代教学技术，特别注重为代表性不足群体的学生创造一个包容的环境。研究和教育活动的进一步整合将通过监督研究生和本科生的研究，并为研究生建立一个期刊俱乐部来实现。技术总结该奖项支持具有重要能带几何的材料的光学和传输性质的理论研究和教育。这一提议的目的是为无序无间隙拓扑相的电动力学、流体力学和输运性质提供理论见解，并发展新的理论方法，有助于揭示电子在实验中行为的各种几何方面。这项研究包括三个主要方向，旨在理解无间隙体系中的光学和输运现象：1.无间隙拓扑相的非局域电动力学和电子流体动力学，包括手征电子流体理论和晶体中的手征涡旋效应。其中一个重点将是研究流体动力系统中的反常霍尔效应。无序手性金属中的非局域输运理论。该活动将包括对动态手征磁效应的外在贡献的研究；无序Dirac系统中非微扰瞬子物理的研究；非均匀和应变拓扑系统中非局域输运理论的发展。Weyl和Dirac金属非平衡态的非线性光学和磁光现象。这项研究将集中于Weyl系统中非线性现象的拓扑学方面，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的电流感生磁光现象的理论。研究将使用广泛的技术：多能带系统的量子动力学方程，巡回无序系统的场论方法，数值模拟，以及从头计算研究。该奖项还支持旨在改善犹他州STEM教育的教育和培训活动。主要工作将针对监督高中物理教师的暑期研究；为高中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性问题；实施现代教学技术，特别注重为代表性不足群体的学生创造一个包容的环境。研究和教育活动的进一步整合将通过监督研究生和本科生的研究，并为研究生建立一个期刊俱乐部来实现。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。