Development of a Ferrimagnetic Terahertz Oscillator

太赫兹(THz)频段的电磁频谱在很大程度上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太赫兹技术的空白，并将太赫兹频段开放给目前受到目前可用大型和/或低温太赫兹源限制的应用。该项目将在科学和工程的跨学科领域培养2000名研究生和至少2000名本科生。社区大学生和代表性不足的少数民族大学生将被纳入暑期研究项目。这项研究的结果将被纳入材料科学与工程系的课程作业，包括向公众免费提供的在线课程。PIS将在剑桥科学节期间组织纳米天文台，向公众解释光刻和显微镜，并将通过Dow-MIT Access多样性计划提供纳米技术方面的讲座和活动。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型太赫兹(THz)源。电磁频谱的太赫兹频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高效的、可调谐的宽带太赫兹光源，以及在小型设备中实现它们的手段。这项拟议的研究将展示一种革命性的频率可调固态太赫兹发射器，其品质因数是当前技术水平所无法比拟的。使所提出的THz源成为可能的关键创新是在其角动量补偿点附近被驱动进入THz进动的亚铁磁体中的大未补偿净磁化的偶极辐射。在反铁磁交换作用能够实现超快动力学的低阻尼氧化亚铁磁体中，自旋霍尔电流驱动的相干自激振荡频率将超过1 THz。基础研究将对高速反铁磁类自旋动力学和自旋-电荷相互转化产生新的见解，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。可调谐的自旋电子太赫兹发生器将作为概念验证紧凑型太赫兹源。该项目将培养两名研究生和两名本科生。研究结果将被纳入材料科学与工程系的课程作业。公众活动将包括剑桥科学节期间的纳米天文台，以及通过道氏-麻省理工学院获取多样性计划在纳米技术方面的讲座和活动。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。

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.