Investigation of Interface Structure-Property Relationship of Transition-Metal Oxides by in-Situ Materials Growth with Atomic Precision

摘要：未来的电子产品将需要新的材料和材料接口。该项目将材料生长与表征相结合，以原子尺度的精度构建界面结构。这种材料和接口提供了新的和通常意想不到的功能，可以在未来的电子设备中使用。这项工作的总体目标是发展这类新材料界面上产生的科学和技术。研究小组打算推进基本的设计原则，这反过来又可以激发新的电子和磁性状态的创造，用于技术应用。此外，这一努力的一个重要成果是将材料的生长、表征和设计整合到一个研究和教育计划中，以培养未来的科技劳动力，以应对这个技术驱动的社会的新挑战。研究生和本科生都参与材料制造和表征工作。技术摘要：本项目重点研究新型铁磁-超导体结的新型邻近效应及其激发结构-性能关系。利用该项目的原位生长和表征能力，该研究小组打算揭示过渡金属氧化物新界面的结构-性能关系。具体来说，通过利用在半金属锰或普通铁磁氧化膜与非常规超导体之间创建原子尖锐界面的专业知识，该团队旨在解决实现远程自旋极化超电流的突出问题，以及通过改变铁磁层厚度来确定铁磁层结构与自旋极化超电流相干长度之间的相关性。此外，以原子精度实现原位生长和表征的能力可以解决金属超导体结中的几个基本问题，包括Andreev反射的势垒透明度的原子水平控制调谐，以及三重态Josephson结的概念验证。

Non-technical Abstract: Future electronics will require novel materials and material interfaces. This project combines material growth with characterization to construct interface structures with atomic-scale precision. Such materials and interfaces provide new and often unexpected functionalities which can be utilized in future electronic devices. The broad goal of this work is to develop the science and technology arising at interfaces of this class of novel materials. The research team intends to advance the fundamental design principles, which can in turn inspire the creation of new electronic and magnetic states for technological applications. Furthermore, a significant product of this endeavor is to integrate material growth, characterization and design into a research and educational program for the training of the future science and technology workforce that meets new challenges in this technology-driven society. Both graduate and undergraduate students are involved in material fabrication and characterization efforts. Technical Abstract:The focus of this project lies in the novel proximity effects and related exciting structure-property relationship of novel ferromagnet-superconductor junctions. By taking advantage of the project's in-situ growth and characterization capability, this research team intends to uncover the structure-property relationship of the novel interfaces of transition metal oxides. Specifically, by exploiting expertise in creating atomically sharp interfaces between half-metallic manganites or ordinary ferromagnetic oxide films and unconventional superconductors, the team aims to resolve the outstanding issue of realizing long-range spin-polarized supercurrent, as well as determining the correlation between ferromagnetic layer structure and the coherent length of spin-polarized supercurrent by varying ferromagnetic layer thickness. Furthermore, the ability to achieve in-situ growth and characterization with atomic precision allows addressing several fundamental issues in metal-superconductor junctions, including atomic-level controlled tuning of barrier transparency on Andreev reflection, and conceptual validation of triplet Josephson junctions.