CAREER: Multifunctional Heterostructures of Perovskite Structured Materials

非技术描述：下一代自旋电子器件、传感器和低温固体氧化物燃料电池的发展需要开发具有传统块状材料所不具备的新功能特性的材料。一条新的途径涉及利用表面和界面上发生的纳米级结构和化学变化所产生的意想不到的物理现象。这项工作的方法是利用激光辅助生长来控制界面性质，原子层精度与最先进的结构和化学性质表征技术相结合。通过这种方式，可以完全理解从界面机制衍生出的新的磁性和电性的起源。研究活动包括通过NSF加州少数群体参与联盟(CAMP)计划培训本科生和研究生研究人员，包括代表不足的少数群体。此外，科学、技术、工程和数学(STEM)研讨会将来自北加州社区大学的教育困难学生带到加州大学戴维斯分校，亲身体验加州大学戴维斯分校的科学和工程课程能为他们提供什么。技术描述：这份职业计划的目标是了解和利用人工异质结构和纳米复合材料中的表面和界面现象，这些材料具有下一代自旋电子器件、传感器和低温固体氧化物燃料电池所需的多种功能特性。钙钛矿型结构材料因其多样的、可调的功能特性而被选为这项工作的平台。这项工作的独特方面涉及两个同等重要领域的综合专门知识。首先，利用脉冲激光沉积技术制备了化学和结构参数可精确控制的异质结构和纳米复合材料。由嵌入在基质中的孤岛组成的纳米复合材料是通过电子束光刻和离子注入的两步过程的结构修改来定义的。其次，使用复杂的表征技术仔细研究局部表面和界面性质及其对整体功能性质的影响。特别是，采用了基于同步辐射的技术，该技术提供关于每一层的电子结构和磁特性的表面敏感和化学选择性信息。总而言之，这些步骤提供了一种获得表面和界面效应的基本了解的方法，可以利用这些效应来控制材料系统的多功能。

NON-TECHNICAL DESCRIPTION: The development of next generation spintronic devices, sensors, and low temperature solid oxide fuel cells requires the development of materials with new functional properties not found in conventional bulk materials. A novel route involves harnessing the unexpected physical phenomena that result from the changes in structure and chemistry which occur over nanometer scales at surfaces and interfaces. The approach of this work utilizes laser-assisted growth to control interfacial properties with atomic layer precision in combination with state-of-the-art techniques for characterizing the structural and chemical properties. In this way, a full understanding of the origins of new magnetic and electronic properties derived from interfacial mechanisms can be determined. The research activities involve training of undergraduate and graduate researchers, including under-represented minorities through the NSF California Alliance for Minority Participation (CAMP) program. Furthermore, a Science, Technology, Engineering, and Mathematics (STEM) workshop brings educationally disadvantaged students from community colleges around Northern California to UC Davis to experience first hand what the science and engineering programs at UC Davis can offer them. TECHNICAL DESCRIPTION: The objective of this CAREER proposal involves understanding and harnessing surface and interfacial phenomena in artificial heterostructures and nanocomposites which possess multiple functional properties as needed for next generation spintronic devices, sensors, and low temperature solid oxide fuel cells. Perovskite structured materials are chosen as the platform for this work for their diverse and tunable functional properties. The unique aspect of this work involves the combined expertise in two equally important areas. First, heterostructures and nanocomposites with precisely controlled chemical and structural parameters are grown by pulsed laser deposition. Nanocomposites consisting of isolated islands embedded in a matrix are defined by a structural modification through a two-step process of e-beam lithography followed by ion implantation. Second, sophisticated characterization techniques are used to carefully probe both the local surface and interfacial properties and their effect on the overall global functional properties. In particular, synchrotron radiation based techniques which offer surface sensitive and chemically selective information on the electronic structure and magnetic characteristics of each layer are employed. Together, these steps provide a means of gaining a fundamental understanding of surface and interfacial effects which can be harnessed towards the control of the multifunctionality of materials systems.