Exploring van der Waals heterostructure magnetic devices for high-efficiency and high-density memory

探索用于高效高密度存储器的范德华异质结构磁性器件

• 批准号: 2051450
• 负责人: Jing Shi
• 金额: $ 34.5万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2051450&HistoricalAwards=false
• 关键词: Exploring; van; der; Waals; heterostructure

This proposed research will explore van der Waals heterostructure-based magnetic devices capable of delivering highly efficient antidamping spin-orbit torque for switching perpendicular magnetization. Reducing energy dissipation for switching magnetic memory devices is increasingly challenging as the memory density scales up, which calls for innovative ways to greatly enhance the energy efficiency. Perpendicular magnetization with strong anisotropy is a requisite for the stability of high-density memory devices. The proposed research deals with a particular type of the van der Waals heterostructures which are composed of an atomically layered magnet with strong perpendicular magnetic anisotropy such as Fe3GeTe2 and another atomically layered Weyl semimetal with strong spin-momentum locking and low crystalline symmetry such as 1T’-WTe2. Unlike spin-orbit torques created by ordinary three-dimensional, high-symmetry materials, the unique antidamping torque generated by 1T’-WTe2 is expected to result in a much lower critical current density for switching the Fe3GeTe2 magnetization in this van der Waals heterostructure. Along with the atomically flat, chemically and magnetically sharp interface, the combination of these two materials provides unparalleled intrinsic and extrinsic properties suitable for future generations of high-density magnetic random access memory devices. The proposed research will provide excellent opportunities to educate graduate students across disciplines at PI’s institution, especially the underrepresented minority students by enrolling them in a newly developed elective course by the PI on van der Waals heterostructures and by training the student recruited for doing the cutting-edge research in this project.The objectives of this proposed research include (a) fabrication of the proposed van der Waals heterostructure nanoscale devices by exfoliation; (b) characterization of relevant physical properties including the perpendicular magnetic anisotropy constant, and saturation magnetization, and their temperature and thickness dependences, and tuning of magnetic properties such as magnetic anisotropy and Curie temperature; (c) experimental determination of critical switching current density and spin-orbit torque efficiency in the limits of few atomic layers in thickness and sub-100 nm in lateral dimensions; (d) optimization of van der Waals heterostructure materials, interfaces, and device geometry to maximize the energy efficiency. Successful exfoliation and nanoscale device fabrication of atomically thin magnetic materials are very recent scientific achievements and demonstration of the special out-of-plane spin-orbit torque in low-symmetry, atomically layered Weyl semimetal WTe2 was also accomplished recently. Integration of these newly discovered van der Waals materials to form unique heterostructures-based devices represents a bold endeavor that will lead to discoveries of new phenomena and advance the current understanding of materials science and physics of magnetic devices for high-efficiency and high-density memory.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.

这项拟议的研究将探索基于范德华异质结构的磁性器件，该器件能够提供用于切换垂直磁化的高抗阻尼自旋轨道扭矩，随着存储密度的扩大，减少切换磁性存储器件的能量耗散变得越来越具有挑战性，这需要高效的创新。具有强各向异性的垂直磁化是高密度存储器件稳定性的必要条件。所提出的研究涉及特定类型的范德华。瓦尔斯异质结构由具有强垂直磁各向异性的原子层状磁体（例如 Fe3GeTe2）和另一种具有强自旋动量锁定和低晶体对称性的原子层状韦尔半金属（例如 1T'-WTe2）组成，与普通三元材料产生的自旋轨道扭矩不同。三维、高对称性材料，1T'-WTe2 产生的独特抗阻尼扭矩预计将导致低得多的在这种范德华异质结构中切换 Fe3GeTe2 磁化强度的临界电流密度以及原子平坦、化学和磁性尖锐的界面，这两种材料的组合提供了无与伦比的内在和外在特性，适合未来几代高密度磁性随机存取。拟议的研究将为 PI 机构的研究生提供极好的跨学科教育机会，特别是让少数族裔学生参加由 PI 机构新开发的选修课程。范德瓦尔斯异质结构的 PI，并通过培训为该项目进行前沿研究而招募的学生。这项拟议研究的目标包括 (a) 通过剥离制造拟议的范德瓦尔斯异质结构纳米级器件；(b) 表征；相关物理特性，包括垂直磁各向异性常数和饱和磁化强度，及其温度和厚度依赖性，以及磁特性的调整，例如磁各向异性和居里温度（c）实验测定；临界开关电流密度和自旋轨道扭矩效率限制在几个原子层的厚度和亚100纳米的横向尺寸；（d）优化范德华异质结构材料、界面和器件几何形状，以最大限度地提高能量效率。原子薄磁性材料的成功剥离和纳米级器件制造是最近的科学成就，并证明了低对称性、原子层状Weyl半金属WTe2中特殊的面外自旋轨道扭矩最近还完成了将这些新发现的范德华材料集成以形成独特的基于异质结构的器件，这代表了一项大胆的努力，它将导致新现象的发现，并推进目前对材料科学和磁性器件物理学的理解，以实现高效和高性能。高密度存储器。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Wide field imaging of van der Waals ferromagnet Fe3GeTe2 by spin defects in hexagonal boron nitride

通过六方氮化硼中的自旋缺陷对范德华铁磁体 Fe3GeTe2 进行宽场成像

• DOI: 10.1038/s41467-022-33016-2
• 发表时间: 2022-09
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: Huang, Mengqi;Zhou, Jingcheng;Chen, Di;Lu, Hanyi;McLaughlin, Nathan J.;Li, Senlei;Alghamdi, Mohammed;Djugba, Dziga;Shi, Jing;Wang, Hailong;et al
• 通讯作者: et al

Proximity-magnetized quantum spin Hall insulator: monolayer 1 T’ WTe2/Cr2Ge2Te6

邻近磁化量子自旋霍尔绝缘体：单层1-T-WTe2/Cr2Ge2Te6

• DOI: 10.1038/s41467-022-32808-w
• 发表时间: 2022-09-01
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: Li, Junxue;Rashetnia, Mina;Lohmann, Mark;Koo, Jahyun;Xu, Youming;Zhang, Xiao;Watanabe, Kenji;Taniguchi, Takashi;Jia, Shuang;Chen, Xi;et al
• 通讯作者: et al