RII Track-4: Exploring Ferromagnetism in Two-Dimensional Van Der Waals Materials

RII Track-4：探索二维范德华材料中的铁磁性

• 批准号: 1929138
• 负责人: Kai He
• 金额: $ 29.92万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-12-01 至 2022-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1929138&HistoricalAwards=false
• 关键词: RII; Track; Exploring; Ferromagnetism; Two

The current silicon-based information technologies start to approach the physical limit set by the speed and density of electronic transistors. To continue the trend of Moore's Law, the hope is the emergent quantum materials because they may shift the information processing paradigm from controlling the electronic transport to manipulating the spin interaction, thereby eliminating charge transfer and heat dissipation, leading to higher speed, smaller device, and better energy efficiency. This transformative technology is known as "spintronics", which requires the coexistence of magnetic and semiconducting properties. Recent discovery of intrinsic magnetism in two-dimensional (2D) semiconductors is considered as a promising candidate system, whose unique properties are correlated to the electron and spin interactions within the crystal lattices, which needs to be understood at the atomic length scale. This project aims to investigate the magnetic spin textures in such 2D materials using transmission electron microscopy (TEM) whose spatial resolution (1 angstrom) can effectively identify the ultrasmall magnetic characteristics. This work will be performed using the world-class TEM facilities at Brookhaven National Laboratory, where the PI will develop new research expertise and establish long-term collaborations that can greatly enhance the research capacity of Clemson University.The emergence of two-dimensional (2D) materials offers an ideal platform to display exotic physical properties restricted by the quantum confinement, which leads to the groundbreaking discovery of intrinsic 2D magnetism that may have a transformative impact on quantum information technologies. To address the fundamental science questions regarding the charge, spin, and orbital coupling with the crystal lattice in such material systems, the atomistic characterization using transmission electron microscopy (TEM) is essential. The goal of this project is to probe the magnetic spin textures in 2D ferromagnetic crystals and their van der Waals (vdW) heterostructures using TEM-based magnetic imaging techniques. The work will be performed in partnership with researchers at Brookhaven National Laboratory (BNL), which is a worldwide leader in the field of electron microscopy. The PI will employ a unique toolset combining Lorentz microscopy and electron holography to identify the spin textures and elucidate their dependence of extrinsic physical parameters and structural effects in 2D vdW materials with intrinsic magnetic orders. These findings will provide a mechanistic understanding of electron-spin-lattice correlation underpinning the intrinsic 2D magnetic properties and show practical implications for the emerging spintronics applications. This fellowship allows the PI to establish a long-term collaboration between Clemson University and BNL, which, in turn, will strengthen the research activities, expertise, and education for the PI and the whole Clemson community, and thereby enhance the scientific competitiveness, workforce development, and economic growth of the State of South Carolina.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.

目前的硅基信息技术开始接近电子晶体管的速度和密度所设定的物理极限。为了延续摩尔定律的趋势，希望是新兴的量子材料，因为它们可能将信息处理范式从控制电子输运转移到操纵自旋相互作用，从而消除电荷转移和热耗散，导致更高的速度，更小的器件和更好的能量效率。这种变革性的技术被称为“自旋电子学”，它需要磁性和半导体性质的共存。最近发现的二维（2D）半导体中的内禀磁性被认为是一个有前途的候选系统，其独特的性质与晶格内的电子和自旋相互作用相关，这需要在原子长度尺度上理解。该项目旨在使用透射电子显微镜（TEM）研究此类2D材料中的磁自旋纹理，其空间分辨率（1埃）可以有效地识别超小磁性特征。这项工作将使用布鲁克海文国家实验室的世界一流的TEM设备进行，PI将在那里开发新的研究专业知识并建立长期合作，这将大大提高克莱姆森大学的研究能力。二维（2D）材料的出现提供了一个理想的平台来展示受量子限制限制的奇异物理特性，这导致了内在2D磁性的突破性发现，可能对量子信息技术产生变革性影响。为了解决有关电荷，自旋和轨道耦合与晶格在这样的材料系统的基础科学问题，使用透射电子显微镜（TEM）的原子表征是必不可少的。本计画的目的是利用TEM磁成像技术，探讨二维铁磁晶体及其货车德瓦耳斯异质结构的磁自旋织构。这项工作将与布鲁克海文国家实验室（BNL）的研究人员合作进行，该实验室是电子显微镜领域的全球领导者。PI将采用一个独特的工具集结合洛伦兹显微镜和电子全息术，以确定自旋纹理和阐明其外部物理参数的依赖性和结构效应在2D vdW材料与内禀磁序。这些发现将提供一个机械的理解电子自旋晶格相关的内在的二维磁性的基础，并显示新兴的自旋电子学应用的实际意义。该奖学金允许PI建立克莱姆森大学和BNL之间的长期合作，这反过来将加强PI和整个克莱姆森社区的研究活动，专业知识和教育，从而提高科学竞争力，劳动力发展，该奖项反映了NSF的法定使命，并被认为是值得通过评估使用的支持。基金会的学术价值和更广泛的影响审查标准。

项目成果

Origin of anomalous high-rate Na-ion electrochemistry in layered bismuth telluride anodes

• DOI: 10.1016/j.matt.2021.01.005
• 发表时间: 2021-04-07
• 期刊: MATTER
• 影响因子: 18.9
• 作者: Cui, Jiang;Zheng, Hongkui;He, Kai
• 通讯作者: He, Kai

Identification of Topological Spin Textures in Frustrated Fe 3 Sn 2 Magnetic System

受抑Fe 3 Sn 2 磁系中拓扑自旋织构的识别

• DOI: 10.1017/s1431927621003561
• 发表时间: 2021
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: Cui, Jiang;Zheng, Hongkui;Watt, John;He, Kai
• 通讯作者: He, Kai