Development of a Ferrimagnetic Terahertz Oscillator

电磁频谱的太赫兹（THz）波段是一种尚未开发的资源，在成像，光谱学，传感，计算和通信方面具有潜在的应用。该项目旨在通过开发一种在室温下工作的新型紧凑型高功率源来填补THz技术的空白，并将THz频段开放给目前受体积庞大和/或低温THz源限制的应用。该项目将在科学和工程的跨学科领域培养2名研究生和至少2名本科生。社区大学的学生和代表性不足的少数民族大学生将被纳入夏季研究计划。研究结果将纳入材料科学与工程系的课程，包括免费向公众提供的在线科目。在剑桥科学节期间，PI将组织纳米天文台，向公众解释光刻和显微镜，并将通过道-麻省理工学院访问多样性计划提供纳米技术的讲座和活动。拟议工作的目标是通过利用邻近重金属中电流驱动的亚铁磁体的动态振荡行为来设计新颖的太赫兹（THz）源。电磁频谱的THz波段是一种尚未开发的资源，在成像，光谱学，传感，计算和通信方面具有潜在的应用。 阻碍广泛应用的是缺乏有效的、可调谐的宽带THz源，以及在小形状因子设备中实现它们的手段。拟议的研究将展示一个革命性的频率可调谐固态太赫兹发射器的优点是目前的最先进的国家无法比拟的数字。关键的创新，将使拟议的太赫兹源是一个大的未补偿的净磁化驱动到太赫兹进动附近的角动量补偿点的亚铁磁体的偶极辐射。 自旋霍尔电流驱动的相干自振荡频率超过1太赫兹将实现在低阻尼氧化物亚铁磁体，其中反铁磁交换相互作用，使超快动力学。基础研究将产生对高速反铁磁类自旋动力学和自旋-电荷相互转换的新见解，以及设计多轴磁各向异性景观以定制动态磁化轨迹的新方法。 可调谐自旋电子太赫兹发生器将作为概念验证紧凑型太赫兹源。该项目将培训两名研究生和两名本科生。研究结果将纳入材料科学与工程系的课程。公众宣传将包括纳米天文台在剑桥科学节和讲座和活动，纳米技术通过道-麻省理工学院访问多样性program.This奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的智力价值和更广泛的影响审查标准。

The terahertz (THz) band of the electromagnetic spectrum is a largely untapped resource, with potential applications in imaging, spectroscopy, sensing, computing, and communications. This project aims to fill a gap in THz technology by developing a novel compact high-power source that operates at room temperature, and opening up the THz band to applications that are currently limited by the bulky and/or low temperature THz sources available today. The project will train 2 graduate students and at least 2 undergraduate students in an interdisciplinary area of science and engineering. Community college students and underrepresented minority college students will be included in summer research programs. Results from the research will be incorporated into coursework in the Materials Science and Engineering department, including online subjects that are available to the public free. The PIs will organize The NanoObservatory during the Cambridge Science Festival which explains lithography and microscopy to the general public, and will offer lectures and activities in nanotechnology through the Dow-MIT ACCESS diversity program.The objective of the proposed work is to engineer novel terahertz (THz) sources by harnessing the dynamical oscillatory behavior of a ferrimagnet driven by an electric current in an adjacent heavy metal. The THz band of the electromagnetic spectrum is a largely untapped resource, with potential applications in imaging, spectroscopy, sensing, computing, and communications. Standing in the way of widespread applications is a lack of efficient, tunable broadband THz sources, and a means of implementing them in small form factor devices. The proposed research will demonstrate a revolutionary frequency-tunable solid-state THz emitter with figures of merit that are unmatched by the current state of the art. The key innovation that will enable the proposed THz source is the dipole radiation of a large uncompensated net magnetization in a ferrimagnet driven into THz precession near its angular momentum compensation point. Spin-Hall current-driven coherent auto-oscillations with frequency exceeding 1 THz will be achieved in low-damping oxide ferrimagnets in which antiferromagnetic exchange interactions enable ultrafast dynamics. The fundamental research will yield new insights into high-speed antiferromagnetic-like spin dynamics and spin-charge interconversion as well as new approaches to engineer multi-axis magnetic anisotropy landscapes to tailor dynamical magnetization trajectories. The tunable spintronic THz generators will serve as proof-of-concept compact THz sources. The project will train two graduate and two undergraduate students. Results from the research will be incorporated into coursework in the Materials Science and Engineering department. Public outreach will include The NanoObservatory during the Cambridge Science Festival and lectures and activities in nanotechnology through the Dow-MIT ACCESS diversity program.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.