Imaging Ultrafast and Ultrasmall: Understanding and Manipulating Phase Transitions in Correlated Oxides Using Coherent X-Ray Diffraction

非技术描述：现代半导体器件在信息技术、能源、健康和教育等多个领域取得了重要进展。为了克服现有微电子技术性能停滞不前的现状，实现高能效的高速运行，复合氧化物已被确定为半导体的一种可能的替代品。该项目探索了利用光学激光在超快时间尺度上操纵复杂镍氧化物的磁性和电学性质的新方法。研究活动涉及纳米尺度和飞秒时间尺度的复合氧化物的合成和高级表征。对纳米级和超快现象的基本理解预计将对未来几代计算设备的发展产生重大影响。教育活动包括向女性和少数族裔本科生介绍美国国家实验室的机会，并与加州大学戴维斯分校数学工程科学成就(MESA)学校计划合作，让高中生参与科学、技术、工程和数学。该项目将在材料科学、物理和电气工程的交叉学科领域为研究生和本科生提供培训。毕业生很可能在未来的信息技术领域找到工作。技术细节：本研究项目的目标是阐明在相关氧化物(包括镍酸钕和镍酸钐等稀土镍酸盐)中在超短尺度和超快时间尺度上定制材料性能的基本限制和机制。该项目利用基于同步加速器和自由电子激光的相干X射线技术，重点研究稀土镍酸盐薄膜中的光诱导金属-绝缘体相变。具体目标包括：(I)破译与超快行为有关的基本长度尺度和时间尺度，(Ii)了解纳米尺度形态在光学诱导相变中的影响，以及(Iii)研究飞秒时间尺度上电子、磁场和结构自由度的耦合。在该项目中发现的材料行为超快/超微小前沿的终极科学知识将使基于光-物质相互作用的未来几代计算设备的开发成为可能。教育活动包括在美国国家实验室对本科生和研究生进行最先进的沉积和表征工具的培训，包括同步辐射和基于自由电子激光的表征技术。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。

NON-TECHNICAL DESCRIPTION: Modern-day semiconductor devices have led to important advances in diverse areas including information technology, energy, health, and education. To overcome the current plateau in performance of the existing microelectronics and enable energy-efficient high-speed operation, complex oxides have been identified as a possible alternative to semiconductors. This project explores the novel approach of utilizing optical lasers to manipulate magnetic and electronic properties of complex nickel oxides at ultrafast timescales. Research activities involve synthesis and advanced characterization of complex oxides at nanometer lengthscales and femtosecond timescales. The fundamental understanding of nanoscale and ultrafast phenomenon is expected to significantly impact the development of future generations of computing devices. Education activities includes introducing women and minority undergraduate students to opportunities at U.S. National Laboratories and collaborating with University of California Davis Mathematics Engineering Science Achievement (MESA) Schools Program to engage high school students in science, technology, engineering, and mathematics. This project will provide graduate and undergraduate students training in interdisciplinary fields at the intersection of materials science, physics, and electrical engineering. Graduates are likely to find future employment in the information technology sector. TECHNICAL DETAILS: The goal of this research project is to elucidate fundamental limits and mechanisms to tailor material properties at ultrasmall lengthscales and ultrafast timescales in correlated oxides including rare-earth nickelates such as neodymium nickelate and samarium nickelate. The project focuses on optically induced metal-insulator phase transitions in rare earth nickelate thin films by utilizing synchrotron and free electron laser based coherent X-ray techniques. Specific objectives include: (i) deciphering fundamental lengthscales and timescales associated with ultrafast behavior, (ii) understanding the influence of nanoscale morphology in optically induced phase transitions, and (iii) investigating the coupling of electronic, magnetic and structural degrees of freedom at femtosecond timescales. The scientific knowledge at the ultimate limits of the ultrafast/ultrasmall frontier in materials behavior discovered in this project will enable development of future generations of computing devices based on light-matter interactions. Education activities include the training of undergraduate and graduate students in state-of-the art deposition and characterization tools, including synchrotron radiation and free electron laser-based characterization techniques at U.S. National Laboratories.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.