FRG: Quantum Engineering of Metallic and Magnetic Nanostructures

技术：由美国国家科学基金会（NSF）支持，始于1998年，这个FRG计划开发了一种新的“电子生长”概念，强调了流动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以及可能的生长模式方面的重要性。这个新概念为“量子工程”增添了一个实质性的新方面，因为量子效应现在可以用来精确控制量子状态下金属结构的形成。利用PI在金属和磁性纳米结构广泛领域的优势和概念进展，该项目旨在推动三个新领域的研究目标：(a)一维电子生长和一维量子结构；(b)杂化量子结构的亚表面活性剂外延和量子生长；(c)量子膜上的吸附能量、表面迁移率和化学反应性。在区域(a)中，由于一维电子系统在态密度（DOS）中表现出尖锐的尖峰，与二维系统的阶梯DOS相反，人们期望更强的量子尺寸效应。这可能被用于控制一维量子结构的形成。将研究自旋分辨DOS和一维量子生长之间的相互作用。此外，一维超导性将被推向清洁极限，并得到彻底的探索。在区域(b)中，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性半导体的混合量子结构。在这里的成功将允许探索这种混合系统中电荷和自旋操纵的新概念。在(c)领域，pi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量，它们的表面迁移速率，以及在选定的催化金属膜上的化学反应性。非技术：人工设计的降维电子系统在现代材料研究中占有中心地位。通过发展先进的合成技术，材料科学家努力通过尺寸控制来定制具有终极原子精度的新型电子材料。驱动力是人们认识到，在降维空间中，量子效应必然更加明显，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。第一是通过博士后、研究生和本科生的研究培训，培养纳米科学和纳米技术领域的下一代材料科学家。本科学生是通过我们机构的REU项目招收的。下一个目标是通过在两个机构的研究生和本科生阶段开发纳米科学和技术的新课程和新课程来提供更广泛的教育。这一教育目标已经成功实现，并将继续推向新的战线。最后，在K-12纳米科学教育方面，pi将通过德克萨斯大学的UTEACH项目招聘高中科学教师。此外，为了在最基本的层面上介绍纳米科学的概念，pi还与奥斯汀儿童博物馆建立了伙伴关系，为K-5的幼儿开发纳米科学教育的演示套件。田纳西大学已经并将继续进行类似的努力。作为一个具体的例子，一个名叫张的PI，多年来一直在当地一所小学担任志愿科学教师，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.