NIRT: Building Nanospintronic and Nanomagnetic Systems - Growth, Manipulation, and Characterization at the Atomic Scale

在这个NIRT项目中，纳米自旋电子和纳米磁系统将利用一种独特的、前所未有的自旋极化扫描隧道显微镜（SP-STM）、STM原子操纵和理论建模的结合来探索。纳米结构将在分子束外延制备的新型氮化物衬底（包括GaN和Mn3N2表面）上制备，然后引入原子操纵系统。纳米结构将通过选择性地从氮化物表面一个接一个地去除单个原子，然后使用原子操纵将它们放置在磁性和非磁性氮化物表面上、里面和上面的磁性原子来取代它们。将研究磁性原子在氮化物表面的独特插入/提取过程。自始至终，衬底和纳米结构将使用STM进行表征，获得表面和纳米结构的直接真实空间图像，并通过隧道光谱获得电子性质。自旋极化显微镜和光谱学将同时被研究，作为直接探测表面和纳米结构的自旋结构的工具，在过程的每个阶段。实验结果将为解释局域矩与不同密度的非磁性或磁性费米海相互作用的理论提供重要的输入。该项目的理论补充也将涉及德国和巴西科学家的合作努力。这项工作有可能对理解涉及纳米尺度自旋的基本物理学产生重要影响。学生和博士后将获得纳米科学方面的特殊培训机会，并将成为未来的顶尖纳米科学家。该NIRT项目的另一个重要部分是公众宣传。这些项目旨在通过专业媒体、一个有吸引力和信息丰富的纳米科学网站以及直接访问当地的K-12学校，向广大受众介绍纳米科学和纳米技术。纳米自旋电子和纳米磁系统是两个重要的新兴科学领域：自旋电子学和纳米科学的交叉点上的一类新的纳米尺度物体。自旋电子学试图利用电子自旋的特性，这是磁性的基础，而传统电子学目前只利用电子的电荷。这可能导致混合自旋电子器件。纳米科学试图探索和理解只有几个原子大小的物体。这个NIRT项目涉及原子对原子的构建和纳米自旋电子和纳米磁性结构性质的同时测量。纳米结构本身将在磁性和非磁性衬底上构建，使用针状探针，该探针能够通过原子操作一次定位一个原子。表面的原子将被移除，取而代之的是磁性原子，如铁、铬或钴。这样的磁性原子将被定位形成10或20个原子纳米磁体或纳米自旋电子结构。这种纳米级磁铁将是有史以来最小的合成磁铁之一。这种小的自旋电子结构预计对未来的设备很重要。这个NIRT项目不仅可以形成磁性纳米结构，还可以使用针探针对表面进行直接成像。探针尖端还能够测量这些微小纳米结构的电子和磁性能。理论工作将补充这些实验，以提供一个完整的理解，这也将得到来自德国和巴西的外国科学合作者的理论专门知识的帮助。学生和博士后将获得纳米科学方面的特殊培训机会，并将成为未来的顶尖纳米科学家。该NIRT项目的另一个重要部分是公众宣传。这些项目旨在通过专业媒体、一个有吸引力和信息丰富的纳米科学网站以及直接访问当地的K-12学校，向广大受众介绍纳米科学和纳米技术。

In this NIRT project, nanospintronic and nanomagnetic systems will be explored utilizing a unique, unprecedented combination of spin-polarized scanning tunneling microscopy (SP-STM), STM atom manipulation, and theoretical modeling. The nanostructures will be prepared on novel nitride substrates (including GaN and Mn3N2 surfaces) prepared by molecular beam epitaxy and then introduced into the atom manipulation system. The nanostructures will be formed by selectively removing single atoms one by one from the nitride surface and then replacing them with magnetic atoms placed on, in, and above magnetic and nonmagnetic nitride surfaces using atom manipulation. The unique insertion/extraction procedures of magnetic atoms into/out of nitride surfaces will be investigated. From beginning to end, the substrates and nanostructures will be characterized using STM, obtaining direct real space pictures of the surface and the nanostructures, as well as obtaining the electronic properties via tunneling spectroscopy. Spin-polarized microscopy and spectroscopy will be simultaneously under investigation as a tool to directly probe the spin structure of the surfaces and nanostructures at every stage of the process. The experimental results will provide important input for theories to explain the interaction of local moments with non-magnetic or magnetic Fermi seas of varying density. The theoretical complement in this project will also involve the collaborative efforts of scientists from Germany and Brazil. The work has the potential for making important impact in the understanding of the fundamental physics involving spins at the nanoscale. Students and postdocs will receive exceptional training oportunities in nanoscience and will be positioned to become the top nanoscientists of tomorrow. Another important part of this NIRT project is public outreach. The projects seeks to inform a broad audience about nanoscience and nanotechnology via professional media, an attractive and informative nanoscience website, and direct visits to regional K-12 schools.Nanospintronic and nanomagnetic systems are a new class of nanoscale objects at the intersection of two important, emerging scientific fields: spintronics and nanoscience. Spintronics seeks to employ the property of electron spin, which is the basis of magnetism, in conventional electronics which currently makes use only of the electron's charge. This could result in hybrid spin-electronic devices. Nanoscience seeks to explore and understand objects having the dimension of only a few atoms. This NIRT project involves the atom-by-atom construction and simultaneous measurement of the properties of nanospintronic and nanomagnetic structures. The nanostructures themselves will be constructed on both magnetic as well as non-magnetic substrates using a needle-shaped probe which is able to position one atom at a time using atom manipulation. Atoms from the surface will be removed and replaced with magnetic atoms such as iron, chromium, or cobalt. Such magnetic atoms will be positioned to form 10 or 20 atom nanomagnets or nanospintronic structures. Such nanoscale magnets will be some of the smallest synthetic magnets ever made. Such small spintronic structures are expected to be important for future devices. This NIRT project will allow not only the formation of the magnetic nanostructures but also their direct imaging using the needle probe to take pictures of the surface. The probe tip is also able to measure the electronic and magnetic properties of these tiny nanostructures. Theoretical work will complement these experiments to provide a complete understanding which will also be aided by the theoretical expertise of foreign scientific collaborators from Germany and Brazil. Students and postdocs will receive exceptional training oportunities in nanoscience and will be positioned to become the top nanoscientists of tomorrow. Another important part of this NIRT project is public outreach. The projects seeks to inform a broad audience about nanoscience and nanotechnology via professional media, an attractive and informative nanoscience website, and direct visits to regional K-12 schools.