FRG: Quantum Engineering of Metallic and Magnetic Nanostructures

技术：在始于1998年的美国国家科学基金会的支持下，FRG计划开发了一个新的“电子增长”概念，强调了巡回电子的量子尺寸效应在定义半导体衬底上金属薄膜的稳定性和可能的生长模式方面的至关重要。这一新概念为“量子工程”一词增添了一个实质性的新方面，因为现在可以利用量子效应来精确控制量子区域中金属结构的形成。利用PI的优势和迄今为止在金属和磁性纳米结构广泛领域取得的概念进展，该项目旨在推动三个新领域的研究目标：(A)一维(1D)电子生长和一维量子结构；(B)亚表面活性剂外延和混合量子结构；(C)量子膜上的吸附能、表面迁移率和化学反应。在(A)区，由于一维电子系统的态密度(DOS)表现出急剧的尖峰，而不是2D系统的阶梯状DOS，人们预计会有更强的量子尺寸效应。这可能被用来控制一维量子结构的形成。自旋分辨的DOS和一维量子生长之间的相互作用将被研究。此外，一维超导电性将被推向清洁的极限，并得到彻底的探索。在(B)领域，通过整合‘亚表面活性剂外延’和‘电子生长’的概念，PI将制造涉及超导体和稀磁半导体的混合量子结构。这方面的成功将使我们能够探索这种混合系统中电荷和自旋操纵的新概念。在(C)领域，PIs将研究量子稳定性如何影响三个密切相关的表面现象：原子和分子的吸附能级、它们的表面迁移率以及选定的催化金属薄膜上的化学反应活性。非技术性：降维的人工工程电子系统在现代材料研究中占据核心地位。通过开发先进的合成技术，材料科学家努力通过尺寸控制来量身定做具有终极原子精度的新型电子材料。其驱动力是人们意识到，在降维后，量子效应必然会更加明显，并可能导致具有技术意义的有趣的新物理特性。教育目标是多方面的。一是通过博士后、研究生和本科生参与的研究培训，培养纳米科学和纳米技术领域的下一代材料科学家。本科生是通过我们院校的REU计划招收的。下一个目标是通过在这两个机构的研究生和本科生一级开发纳米科学和技术的新课程和新课程，提供更广泛的教育。这一教育目标已经圆满实现，并将继续推向新的战线。最后，在K-12纳米科学教育方面，私人投资机构将通过大学的UTeach计划招聘高中科学教师。得克萨斯州。此外，为了在最基本的层面上介绍纳米科学的概念，私营部门还与奥斯汀儿童博物馆建立了伙伴关系，为从K-5岁起的幼儿开发纳米科学教育示范工具包。田纳西大学已经并将继续做出类似的努力。作为一个具体的例子，一位名叫张的少年已经在当地一所小学担任了多年的志愿科学教师，并将继续这样的努力。

TECHNICAL: Supported by NSF, which began in 1998, this FRG program developed a novel 'electronic growth' concept, stressing the vital importance of quantum size effects of the itinerant electrons in defining the stability as well as the likely growth mode of metallic thin films on semiconductor substrates. This new concept adds a substantial new facet to the phrase 'quantum engineering', in that quantum effects can now be exploited to precisely control the formation of metallic structures in the quantum regime. Capitalizing on PI's strengths and conceptual advances achieved so far in the broad areas of metallic and magnetic nanostructures, this project aims at pushing the research objectives in three new frontiers: (a) One-dimensional (1D) Electronic Growth and 1D Quantum Structures; (b) Subsurfactant Epitaxy and Quantum Growth of Hybrid Quantum Structures; and (c) Adsorption Energetics, Surface Mobility, and Chemical Reactivity on Quantum Films. In area (a), as 1D electronic systems exhibit sharp spikes in the density of states (DOS), as opposed to the staircase DOS of 2D systems, one expects much stronger quantum size effects. This can potentially be exploited for controlling the formation of 1D quantum structures. The interplay between the spin-resolved DOS and 1D quantum growth will be investigated. In addition, 1D superconductivity will be pushed toward the clean limit and thoroughly explored. In area (b), by integrating the concepts of 'subsurfactant epitaxy' and 'electronic growth', the PIs will fabricate hybrid quantum structures involving superconductors and dilute magnetic semiconductors. Success here will allow to explore the novel concept of charge and spin manipulation in such hybrid systems. In area (c) the PIs will investigate how the quantum stability influences three intimately related surface phenomena: adsorption energetics of atoms and molecules, their surface migration rates, and chemical reactivity on selected catalytic metal films. NON-TECHNICAL: Artificially engineered electronic systems in reduced dimensions occupy a central part in modern materials research. By developing advanced synthesis techniques, materials scientists strive to tailor novel electronic materials through dimensional control with the ultimate atomic precision. The driving force is the realization that, in reduced dimensions, quantum effects are bound to be more pronounced, and may result in intriguing new physical properties of technological significance. The educational goals are manifold. The first is to prepare the next generation of materials scientists in nanoscience and nanotechnology through research training involving postdoctoral researchers, graduate students, and undergraduates. Undergraduate students are recruited through the REU programs in our institutions. The next goal is to provide broader education through the development of a new curriculum and new courses in nanoscience and technology at the graduate and undergraduate levels at both institutions. This educational goal has been achieved successfully and will continue to be pushed to new fronts. Finally, in terms of K-12 nanoscience education, the PIs will recruit high school science teachers through the UTEACH program at Univ. of Texas. In addition, to introduce the concept of nanoscience at the most basic level the PIs also foster a partnership with the Austin Children's Museum to develop demonstration kits for nanoscience education for young children from K-5. Similar efforts have been and will continue to be made at the University of Tennessee. As a specific example, one PI, Zhang, has served as a volunteer science instructor in a local primary school for years and will continue on such efforts.