Magnetization manipulation and antiferromagnetic dynamics driven by spin current in Weyl semimetals

外尔半金属中自旋电流驱动的磁化操纵和反铁磁动力学

• 批准号: 2210510
• 负责人: Simranjeet Singh
• 金额: $ 39.01万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2210510&HistoricalAwards=false
• 关键词: Magnetization; manipulation; antiferromagnetic; dynamics; driven

Non-technical abstract:Control of the magnetic properties in solid-state materials is key to the operation of many devices that are extensively used in daily life. Applications of such devices include data storage in computers, data encryption on credit cards, and high-frequency signal generation, to name a few. Conventionally, the control of magnetic state is obtained by using an externally applied magnetic field, but this restricts the physical footprint and operational speed of these devices. However, the control of the magnetic state in ferromagnetic and antiferromagnetic materials by other means, such as utilizing electric field or charge current, can overcome these limitations, and potentially realize more advanced nanoscale devices for generating, transmitting, and processing signals at extremely high speeds. However, the fundamental understanding of electric current-induced control and spin dynamics of the magnetic state in ferromagnetic and antiferromagnetic materials is still in its infancy. This project will study an emergent quantum solid-state material platform, namely Weyl semimetals, to demonstrate control of the magnetic state through electric charge current. In these quantum materials, the atoms are arranged in a special configuration that gives rise to unique properties, which in turn allow for an efficient control of magnetic state in ferromagnetic materials and induce spin dynamics in antiferromagnetic materials. The success of this research project will lay the foundation to build a comprehensive understanding of electric charge current-induced spin manipulation and dynamics in magnetic materials, which will have far reaching implications for the emerging field of quantum spintronics. Furthermore, this research project will provide research experience, training, and active mentorship to undergraduate students from a collaborating minority serving institution. Connections with middle school and high school teachers in the greater Pittsburgh area will be established to develop physics demonstrations with detailed lesson plans on the topics of electricity and magnetism. Technical abstract:An energy efficient and field-free manipulation of the magnetic order, i.e., net magnetization of a ferromagnet or Néel vector of an antiferromagnet, using electric field induced spin current is key to realize advanced spintronic applications that include ultra-fast magnetic memory devices, terahertz oscillators, and magnonic devices for generation, transmission, and detection of high-frequency signals. On the other hand, topological materials with lower crystal symmetries, such as Weyl semimetals, host spin-momentum locked electronic states that can lead to an efficient charge to spin transduction and a plethora of other novel phenomena that are highly relevant for quantum spintronics. This research project will utilize crystalline thin films of van der Waals based Weyl semimetals and couple them with a variety of magnetic systems to build atomically sharp superlattices for studying spin manipulation and spin dynamics. The scientific objectives of this research project are two-fold: (1) To obtain a time resolved and spatially resolved view on the underlying mechanisms of field-free spin-orbit torque switching of magnetization in semiconducting and insulating ferromagnets. (2) To study spin-current induced Néel vector dynamics in easy plane antiferromagnets and subsequent spin-pumping from antiferromagnets by exploiting out-of-plane oriented spin current in Weyl semimetals. This research objective is aimed at demonstrating the working principle of an antiferromagnetic oscillator.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.

非技术摘要：控制固态材料的磁特性是日常生活中广泛使用的许多设备运行的关键，此类设备的应用包括计算机中的数据存储、信用卡上的数据加密以及高科技。举几个例子，传统上，磁状态的控制是通过使用外部施加的磁场来实现的，但这限制了这些设备的物理足迹和操作速度。和反铁磁通过其他方式（例如利用电场或充电电流）材料可以克服这些限制，并有可能实现更先进的纳米级器件，以极高的速度生成、传输和处理信号。然而，对电流感应控制的基本理解。铁磁和反铁磁材料中磁态的自旋动力学仍处于起步阶段，该项目将研究一种新兴的量子固态材料平台，即韦尔半金属，以证明通过电荷电流控制这些材料的磁态。量子材料中，原子以特殊的排列方式排列，从而产生独特的性质，从而可以有效控制铁磁材料中的磁态并诱导反铁磁材料中的自旋动力学。该研究项目的成功将为该研究项目的成功奠定基础。建立对磁性材料中电荷电流引起的自旋操纵和动力学的全面理解，这将对新兴的量子自旋电子学领域产生深远的影响。此外，该研究项目将为本科生提供研究经验、培训和积极指导。学生来自一个将与大匹兹堡地区的中学和高中教师建立联系，以开发有关电和磁主题的详细课程计划的物理演示：技术摘要：节能和无场操纵。磁序，即铁磁体的净磁化强度或反铁磁体的尼尔矢量，使用电场感应自旋电流是实现包括超快磁存储器件、太赫兹在内的先进自旋电子应用的关键另一方面，具有较低晶体对称性的拓扑材料（例如外尔半金属）具有自旋动量锁定的电子态，可以产生有效的电荷。自旋传导以及与量子自旋电子学高度相关的大量其他新现象该研究项目将利用基于范德华的外尔半金属的晶体薄膜，并将它们与各种磁系统耦合起来。构建原子级锐超晶格用于研究自旋操纵和自旋动力学该研究项目的科学目标有两个：（1）获得无场自旋轨道扭矩切换的基本机制的时间分辨和空间分辨视图。 (2) 研究易平面反铁磁体中的自旋流感应尼尔矢量动力学以及随后的反铁磁体自旋泵浦面外定向自旋电流反映在外尔半金属中。该研究目标旨在展示反铁磁振荡器的工作原理。该奖项是法定使命，通过使用基金会的智力价值和更广泛的影响审查进行评估，被认为值得支持。标准。