Topological Physics and Light Matter Interactions: From Floquet Topological Insulators to Solar Cells

拓扑物理和光物质相互作用：从Floquet拓扑绝缘体到太阳能电池

• 批准号: 1410435
• 负责人: Gil Refael
• 金额: $ 32.67万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1410435&HistoricalAwards=false
• 关键词: Topological; Physics; Light; Matter; Interactions

NON-TECHNICAL SUMMARYThe Division of Materials Research and the Division of Physics contribute funds to this award which supports theoretical research and education focused on means to stabilize and utilize topological behavior through light-matter interactions in a variety of systems. Topological insulators possess some amazing properties such as the ability to conduct electricity without dissipation at their boundaries while being insulating through their interior. The research which will be carried out under this award is geared toward extending concepts of topological behavior of matter when it interacts with light. This presents a fertile ground for fundamental and applied research. The research will concentrate on three themes. The first is to employ topological insulator surfaces for energy harvesting and detection of infra-red light. The second is to use light to turn an ordinary insulator into a topological insulator. The third is to create unique edge states in a hybrid system of a semiconductor in a cavity that could bridge semiconductor and optical technologies. This research has the potential of introducing new techniques for energy harvesting and light detection and paving the way to new photonic devices based on topological principles. The award will allow training of graduate students and postdocs in an interdisciplinary research environment at the intersection of materials physics and optics. The PI will involve undergraduate students in this research and incorporate the research material into the undergraduate level course that he has developed at Caltech.TECHNICAL SUMMARYThe Division of Materials Research and the Division of Physics contribute funds to this award which supports theoretical research and education focused on means to stabilize and utilize topological behavior through light-matter interactions in a variety of systems. The first part of the project is focused on turning the surface of three-dimensional (3D) topological insulators into a photovoltaic platform aimed at the elusive mid-wavelength infrared spectrum. The surface electrons of 3D topological insulators typically have a minute photocurrent response to incident light in spite of the fact that many electron-hole pairs form. The PI will exploit the spin-orbit locking on the surface to turn it into a photocurrent rectifier. This can be done using a magnetic grating deposited on the surface which should result in a substantial photocurrent response to circularly polarized light. The PI will consider the manifestations of this effect in realistic topological insulators, its optimization with respect to the magnetic pattern deposited, and its extension to other systems, such as two-dimensional (2D) topological insulators and 2D quantum wells with Rashba interaction. In the second part the PI will study ways to induce topological behavior in trivial semiconductors using coherent light. Electrons in semiconductors driven into a topological phase exhibit a non-equilibrium energy distribution determined by the strength of the drive and various relaxation mechanisms. By deriving these distributions, the PI will investigate under what circumstances the non-equilibrium effects do not obstruct the topological behavior of the driven system, and analyze schemes to detect this so-called Floquet topological phase.The third part of the project is focused on the possibility of creating topological polariton states in optical waveguides coupled to trivial semiconductors. Relying on the idea of the Floquet topological insulator, the PI will examine whether it is possible to have a topological bound state of a cavity photon and an exciton in a topologically trivial semiconducting quantum well. A topological polariton state may exhibit strongly enhanced lifetimes, as well as could be used as a nanophotonic isolator. This research has the potential of introducing new techniques for energy harvesting and light detection and paving the way to new photonic devices based on topological principles. The award will allow training of graduate students and postdocs in an interdisciplinary research environment at the intersection of materials physics and optics. The PI will involve undergraduate students in this research and incorporate the research material into the undergraduate level course that he has developed at Caltech.

非技术总结材料研究部和物理部为该奖项提供资金，该奖项支持理论研究和教育，重点是通过各种系统中的光物质相互作用稳定和利用拓扑行为的方法。 拓扑绝缘体具有一些令人惊讶的特性，例如能够在其边界处导电而不耗散，同时通过其内部绝缘。 这项研究将在该奖项下进行，旨在扩展物质与光相互作用时的拓扑行为概念。 这为基础和应用研究提供了肥沃的土壤。研究将集中在三个主题上。第一个是采用拓扑绝缘体表面进行能量收集和红外光检测。第二种是利用光将普通绝缘体变成拓扑绝缘体。 第三个是在腔中半导体的混合系统中创建独特的边缘状态，可以桥接半导体和光学技术。 这项研究有可能引入新的能量收集和光探测技术，并为基于拓扑原理的新光子器件铺平道路。该奖项将允许研究生和博士后在材料物理和光学交叉的跨学科研究环境中进行培训。PI将让本科生参与这项研究，并将研究材料纳入他在加州理工学院开发的本科课程中。技术摘要材料研究部和物理部为该奖项提供资金，该奖项支持理论研究和教育，重点是通过各种系统中的光物质相互作用稳定和利用拓扑行为。该项目的第一部分重点是将三维（3D）拓扑绝缘体的表面变成光伏平台，目标是难以捉摸的中波长红外光谱。三维拓扑绝缘体的表面电子通常对入射光具有微小的光电流响应，尽管事实上形成了许多电子-空穴对。PI将利用表面上的自旋轨道锁定将其变成光电流整流器。 这可以使用沉积在表面上的磁光栅来完成，该磁光栅应该导致对圆偏振光的显著光电流响应。PI将考虑这种效应在现实拓扑绝缘体中的表现，其相对于沉积的磁性图案的优化，以及其对其他系统的扩展，例如二维（2D）拓扑绝缘体和具有Rashba相互作用的2D量子威尔斯。在第二部分中，PI将研究如何使用相干光在平凡的半导体中诱导拓扑行为。半导体中的电子被驱动进入拓扑相，表现出由驱动强度和各种弛豫机制决定的非平衡能量分布。通过推导这些分布，PI将调查在什么情况下的非平衡效应不妨碍驱动系统的拓扑行为，并分析方案，以检测这种所谓的Floquet拓扑phase.The第三部分的项目是集中在创建拓扑极化激元状态耦合到平凡的半导体光波导的可能性。 依靠Floquet拓扑绝缘体的想法，PI将研究是否可能在拓扑平凡的半导体量子阱中具有腔光子和激子的拓扑束缚态。 拓扑极化激元态可以表现出强烈增强的寿命，以及可以用作纳米光子隔离器。这项研究有可能引入新的能量收集和光探测技术，并为基于拓扑原理的新光子器件铺平道路。该奖项将允许研究生和博士后在材料物理和光学交叉的跨学科研究环境中进行培训。PI将让本科生参与这项研究，并将研究材料纳入他在加州理工学院开发的本科课程。