CAREER: Spin-Spin Interactions, Magnetic Order and Low-Dimensional Effects in Magnetic Semiconductors: Education and Research at the Nanoscale with Spin-Polarized STM

在过去的几年里，新一代自旋器件（自旋电子学）的可能性推动了对磁系统的基础研究。与传统的充电电子设备相比，基于自旋的设备具有更快、更低功耗的潜力。稀磁半导体（DMS）是目前实现自旋电子器件最有前途的途径之一，但缺乏在室温下具有磁性载流子的半导体仍然是这一努力的一个重要瓶颈。这个教师早期职业项目的目标是利用扫描隧道显微镜（STM）和一种相对较新的技术，自旋极化STM （SP-STM）来探索稀磁半导体的基本特性。SP-STM在揭示原子长度尺度的磁性方面具有巨大的潜力。了解稀磁性半导体中自旋和电荷行为的细节，可能为使自旋电子技术可行指明道路。这个综合项目将利用纳米科学和纳米技术领域的兴奋来吸引初高中学生对科学感兴趣。本项目拟议的外联活动旨在寻找有效方法，缩小物理和工程领域相当大的性别差距。技术摘要：意想不到的相位和有趣的现象是涉及相互作用量子自旋的系统的标志。磁性半导体也是如此，最近有报道称，自旋库仑阻力、自旋扭矩效应以及在自旋电子器件中应用的巨大潜力，引领着人们走向一个令人兴奋的新领域。本学院早期职业项目的目标是利用低温扫描隧道光谱和一种相对较新的技术，自旋极化STM (SP-STM)，在纳米尺度上探索稀磁半导体的基本特性。SP-STM对这些自旋电子材料的研究将揭示重要的基础物理学以及与材料相关的问题，如：（a)自旋-自旋相互作用和磁畴的有效长度尺度，(b)短程相互作用如何导致长距离有序，c）团簇/沉淀对磁有序的影响以及(d)电子和磁性能如何随维度变化。该提案的教育和推广部分与项目的研究目标紧密地交织在一起。在所有的拓展计划中，一个反复出现的主题将是通过展示纳米尺度科学的最新进展和未来应用的潜力，来激发对物理和技术的兴趣。

Non-technical abstractIn the last few years, the possibility of a new generation of spin based devices (spintronics), has given impetus to fundamental studies of magnetic systems. Spin based devices have the potential to be faster and consume less power than traditional charge based electronics. Dilute magnetic semiconductors (DMS) are currently being pursued as one of the most promising avenues of realizing spintronic devices, but the lack of semiconductors with magnetic carriers at room temperature remains a significant bottleneck in this endeavor. The goal of this Faculty Early Career project is to explore the fundamental properties of dilute magnetic semiconductors using scanning tunneling microscopy (STM) and a relatively new technique, spin-polarized STM (SP-STM). SP-STM has tremendous potential to shed light on magnetic properties at atomic length scales. Understanding the details of the behaviour of spin and charge in dilute magnetic semiconductors might point the way towards making spintronic technology viable. This integrated project will capitalize on the excitement in the field of nanoscience and nanotechnology to attract middle and high school students to the sciences. The proposed outreach activities in the project are geared towards finding effective methods of decreasing the substantially large gender-gap in physics and engineering.Technical AbstractUnexpected phases and interesting phenomena are the hallmarks of systems involving interacting quantum spins. So it is with magnetic semiconductors, with recent reports of spin Coulomb drag, spin-torque effect, and a strong potential for applications in spintronic devices, leading the way to what promises to be an exciting new field. The goal of this Faculty Early Career project is to explore the fundamental properties of dilute magnetic semiconductors at the nanoscale using low temperature scanning tunneling spectroscopy and a relatively new technique, spin-polarized STM (SP-STM). SP-STM studies on these spintronic materials will shed light on important basic physics as well as materials related issues such as: (a) effective length scales of spin-spin interactions and magnetic domains, (b) how short range interactions lead to long range order, c) effect of clusters/precipitates on magnetic order and (d) how electronic and magnetic properties change with dimensionality. The education and outreach components of this proposal are strongly intertwined with the research goals of the project. A recurring theme in all outreach programs will be to generate excitement for physics and technology by exposure to recent advances in nanoscale science and potential for future applications.