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A combined theory-experiment study of electronic, magnetic and thermal properties of complex oxide nano-structures

复合氧化物纳米结构电、磁、热性能的理论与实验相结合研究

基本信息

批准号：
1831406
负责人：
Robert Klie
金额：
$ 64.52万
依托单位：
University of Illinois at Chicago
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-15 至 2023-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1831406&HistoricalAwards=false
关键词：
combined theory experiment study electronic

项目摘要

NON-TECHNICAL DESCRIPTION: Transition metal ceramics exhibit a wide range of properties and functionalities, making them the ideal materials for many next generation electronic devices and sensors. However, the response of many transition metal ceramics to external stimuli, such as heat or electro-magnetic fields remains unknown. This is especially true when the size of device structures is approaching the nanometer scale and the response of the material differs from that observed in the bulk. In this project, a novel approach is explored for measuring, at the nanometer scale, the response of transition metal ceramics to changes in temperature or applied electric or magnetic fields. The combined experimental/theoretical approach is then used to quantify and control the magnetic, electronic and thermal transport properties at interfaces in nanoscale transition metal ceramic materials. The project's research activities center around education and training of science and engineering undergraduate and graduate students. Recruitment and training focuses on the next generation of researchers, in particular involving students from underrepresented groups and minorities through the National Name Exchange program and partnership with local high schools. The participation of undergraduate students in active research projects is fostered through the PI's Journal of Undergraduate Research at the University of Illinois at Chicago. Graduates typically find employment in academia, National Laboratories or industry, including semiconductor companies. TECHNICAL DETAILS: The objectives of this research project are to develop a fundamental understanding of the atomic-scale mechanisms that govern the electronic, magnetic and thermal properties of transition metal perovskite oxide hetero-structures. Two transition ceramic systems are studied, one exhibiting novel magnetic and transport properties below a specific film thickness and the other showing ferroelectric properties and the potential existence of a 2-dimensional electron gas. A combination of in-situ scanning transmission electron microscopy and first-principles density functional theory (DFT) calculations is used together with thin-film and nano-particle synthesis. The project consists of two tasks: 1) Utilizing a novel approach towards measuring the thermal expansion coefficient with nanometer resolution and exploring whether this approach can be utilized to quantify the thermal expansion and transport across substrate/film interfaces. This approach is based on measuring the plasmon peak shift as a function of temperature combined with ab-initio modeling of the materials' dielectric response. 2) Understanding the magnetic and electric transport properties of perovskite oxide thin films. The transport anomalies in ultra-thin cobalt-oxide epitaxial films are examined and compared to films grown on different substrates. The effects of interfacial charges on the electronic structure and ferroelectric polarization of Ti-oxides on compound semiconductor substrates are examined. The integration of research and education through the training of undergraduate and graduate students in state-of-the-art in-situ scanning transmission electron microscopy and theoretical materials physics is an integral feature of this project.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：过渡金属陶瓷具有广泛的特性和功能，使其成为许多下一代电子设备和传感器的理想材料。然而，许多过渡金属陶瓷对外部刺激（如热或电磁场）的响应仍然未知。当器件结构的尺寸接近纳米尺度，并且材料的响应不同于在体中观察到的响应时，这一点尤其正确。在这个项目中，探索了一种在纳米尺度上测量过渡金属陶瓷对温度或外加电场或磁场变化的响应的新方法。结合实验/理论方法，然后用于量化和控制纳米级过渡金属陶瓷材料界面的磁性、电子和热输运性质。该项目的研究活动围绕理工科本科生和研究生的教育和培训展开。招募和培训的重点是下一代研究人员，特别是通过全国姓名交换计划和与当地高中的伙伴关系，让来自代表性不足的群体和少数民族的学生参与进来。通过伊利诺伊大学芝加哥分校的PI本科生研究期刊，鼓励本科生参与积极的研究项目。毕业生通常会在学术界、国家实验室或包括半导体公司在内的工业领域找到工作。技术细节：本研究项目的目标是发展对过渡金属钙钛矿氧化物异质结构的电子、磁性和热性能的原子尺度机制的基本理解。研究了两种过渡陶瓷体系，一种表现出特定薄膜厚度下的新磁性和输运性质，另一种表现出铁电性质和二维电子气体的潜在存在。结合原位扫描透射电子显微镜和第一性原理密度泛函理论（DFT）计算与薄膜和纳米粒子合成。该项目包括两个任务：1)利用纳米分辨率测量热膨胀系数的新方法，并探索该方法是否可以用于量化基片/薄膜界面的热膨胀和输运。该方法基于测量等离子体峰值位移作为温度的函数，并结合材料介电响应的从头算模型。2)了解钙钛矿氧化物薄膜的磁性和电输运性质。研究了超薄钴氧化物外延薄膜中的输运异常，并与生长在不同衬底上的薄膜进行了比较。研究了界面电荷对复合半导体衬底上钛氧化物的电子结构和铁电极化的影响。通过培养本科生和研究生在最先进的原位扫描透射电子显微镜和理论材料物理学方面的研究和教育的整合是这个项目的一个整体特征。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。