CAREER: Confining Magnetism to Two-Dimensions in Transition Metal Oxide Atomic Layers

职业：将磁性限制在过渡金属氧化物原子层的二维范围内

• 批准号: 1751455
• 负责人: Divine Kumah
• 金额: $ 58.95万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1751455&HistoricalAwards=false
• 关键词: CAREER; Confining; Magnetism; Two; Dimensions

NON-TECHNICAL DESCRIPTION: As the dimensions of materials in modern devices approach thicknesses close to a few atomic layers, small deviations in atomic arrangements can occur leading to electronic and magnetic properties which differ vastly from the properties of the bulk materials. Using advanced synthesis tools which permit the combination of atomic layers of materials with different compositions, the atomic deviations can be effectively manipulated to produce novel effects. In this project, high-intensity X-rays are used to image the atomic-scale structure of the interfaces of layers of thin crystalline oxide films. The information gained from imaging these materials is required to help scientists and engineers understand why some oxide materials lose their useful magnetic properties when their thicknesses are reduced to a few atomic layers. The X-ray results are combined with high-resolution electron microscopy, magnetic and transport measurements, and theoretical calculations to design specific combinations of oxide materials to achieve magnetism in single layers of oxide materials. This project has exciting implications for the design of novel materials and devices for information processing, quantum computing and low-powered sensors. This project provides a highly collaborative environment and access to advanced technical resources for training undergraduate and graduate students in the development of the next generation of advanced nanoscale materials. The project provides low-cost tools for visualizing abstract concepts related to crystallography to foster the public understanding of the development of new technologically-relevant crystalline materials.TECHNICAL DETAILS: This project uses state-of-the-art synchrotron X-ray facilities at the Argonne National Laboratory and the Berkeley National Laboratory to carry out three-dimensional non-destructive atomic-scale mapping of the atomic, electronic and magnetic structures of magnetic perovskite oxide surfaces and interfaces. This research provides a comprehensive understanding of the fundamental interactions which occur at the interfaces between atomically-thin magnetic oxide films and other polar and non-polar perovskite materials and establishes a link between the observed interactions and the physical properties of these systems. A combination of first principles theory, high-resolution electron microscopy and temperature-dependent magnetic, transport and element-specific synchrotron X-ray magnetic dichroism measurements is used to design novel oxide heterointerfaces for achieving the confinement of ferromagnetism in two-dimensional oxide layers. These materials have applications in novel spin-based electronic devices. The wide range of cutting-edge research tools utilized in this activity are used to enhance the education of undergraduate and graduate students to prepare them for careers in scientific research and materials and device engineering. An important component of this project is the development of low-cost augmented reality tools for visualizing complex atomic and electronic structures for classroom instruction and public outreach to K-12 schools.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.

非技术描述：随着现代器件中材料的尺寸接近几个原子层的厚度，原子排列中可能会出现微小的偏差，导致电子和磁性特性与块体材料的特性有很大不同。使用允许组合具有不同成分的材料的原子层的先进合成工具，可以有效地操纵原子偏差以产生新颖的效果。在该项目中，使用高强度 X 射线对薄晶体氧化物薄膜层界面的原子级结构进行成像。从这些材料成像中获得的信息有助于科学家和工程师理解为什么某些氧化物材料在厚度减小到几个原子层时会失去其有用的磁性。 X射线结果与高分辨率电子显微镜、磁性和传输测量以及理论计算相结合，设计氧化物材料的特定组合，以实现单层氧化物材料的磁性。该项目对于信息处理、量子计算和低功率传感器的新型材料和设备的设计具有令人兴奋的影响。该项目提供了高度协作的环境和先进的技术资源，用于培训本科生和研究生开发下一代先进纳米材料。该项目提供低成本工具，用于可视化与晶体学相关的抽象概念，以促进公众对新技术相关晶体材料开发的理解。技术细节：该项目使用最先进的同步加速器 X 射线设施阿贡国家实验室和伯克利国家实验室对磁性钙钛矿氧化物表面和界面的原子、电子和磁性结构进行三维无损原子尺度测绘。这项研究提供了对原子薄磁性氧化物薄膜与其他极性和非极性钙钛矿材料之间界面处发生的基本相互作用的全面理解，并在观察到的相互作用与这些系统的物理性质之间建立了联系。结合第一原理理论、高分辨率电子显微镜和温度相关的磁性、输运和元素特定的同步加速器X射线磁二色性测量来设计新型氧化物异质界面，以实现二维氧化物层中铁磁性的限制。这些材料在新型自旋电子器件中具有应用。该活动中使用的广泛的尖端研究工具用于加强本科生和研究生的教育，为他们从事科学研究以及材料和设备工程的职业做好准备。该项目的一个重要组成部分是开发低成本的增强现实工具，用于可视化复杂的原子和电子结构，用于课堂教学和 K-12 学校的公共宣传。该奖项反映了 NSF 的法定使命，并通过评估被认为值得支持利用基金会的智力优势和更广泛的影响审查标准。

项目成果

Thickness and temperature dependence of the atomic-scale structure of SrRuO 3 thin films

SrRuO 3 薄膜原子尺度结构的厚度和温度依赖性

• DOI: 10.1063/5.0087791
• 发表时间: 2022-05
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: Zhang, Xuanyi;Penn, Aubrey N.;Wysocki, Lena;Zhang, Zhan;van Loosdrecht, Paul H.;Kornblum, Lior;LeBeau, James M.;Lindfors;Kumah, Divine P.
• 通讯作者: Kumah, Divine P.

Anisotropic superconductivity at KTaO 3 (111) interfaces

KTaO 3 (111) 界面的各向异性超导

• DOI: 10.1126/sciadv.adf1414
• 发表时间: 2023-02
• 期刊: Science Advances
• 影响因子: 13.6
• 作者: Arnault, Ethan G.;Al;Salmani;Muller, David A.;Kumah, Divine P.;Bahramy, Mohammad S.;Finkelstein, Gleb;Ahadi, Kaveh
• 通讯作者: Ahadi, Kaveh

Superconducting phase of TixOy thin films grown by molecular beam epitaxy

分子束外延生长 TixOy 薄膜的超导相

• DOI: 10.1103/physrevmaterials.6.064805
• 发表时间: 2022-06
• 期刊: Physical Review Materials
• 影响因子: 3.4
• 作者: Ozbek, Yasemin;Brooks, Cooper;Zhang, Xuanyi;Al;Stoica, Vladmir A.;Zhang, Zhan;Kumah, Divine P.
• 通讯作者: Kumah, Divine P.

Correlating Polar Distortions and Interfacial Charge at the Polar/Non-polar LaCrO$_3$/SrTiO$_3$ (001) Interface

极性/非极性 LaCrO$_3$/SrTiO$_3$ (001) 界面处的极性畸变和界面电荷的关联

• DOI: 10.1063/5.0002298
• 发表时间: 2020-04
• 期刊: AIP advances
• 影响因子: 1.6
• 作者: Al;Kumah, Divine P.
• 通讯作者: Kumah, Divine P.

Suspended single-crystalline oxide structures on silicon through wet-etch techniques: Effects of oxygen vacancies and dislocations on etch rates

通过湿法蚀刻技术在硅上悬浮单晶氧化物结构：氧空位和位错对蚀刻速率的影响

• DOI: 10.1116/1.5135035
• 发表时间: 2020-01
• 期刊: Journal of Vacuum Science & Technology A
• 影响因子: 2.9
• 作者: Lim, Zheng Hui;Chrysler, Matthew;Kumar, Abinash;Mauthe, Jacob P.;Kumah, Divine P.;Richardson, Chris;LeBeau, James M.;Ngai, Joseph H.
• 通讯作者: Ngai, Joseph H.