InSb Heterostructures for Spin and Quantum Electronic Experiments

用于自旋和量子电子实验的 InSb 异质结构

• 批准号: 0510056
• 负责人: Michael Santos
• 金额: --
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0510056&HistoricalAwards=false
• 关键词: InSb; Heterostructures; Spin; Quantum; Electronic

TECHNICAL EXPLANATION This project explores spin properties and quantum effects in InSb heterostructures, and aims to optimize such structures for applications that rely on these phenomena. The number of experiments that focus on spin properties of electrons in semiconductors has increased substantially in recent years. Much of this effort is motivated by a vision of new types of devices that exploit spin-polarized currents. Many challenges remain, including finding the most efficient materials and configurations for spin injection and spin manipulation, and developing a range of techniques for characterizing spin properties. The requirement of ballistic transport for some devices provides an additional challenge. Narrow band gap materials are a promising solution since large spin effects caused by the Rashba, Dresselhaus, and Zeeman energy terms are correlated with narrow gaps. Because InSb has the smallest band gap of any III-V semiconductor, spin effects are expected to be among the largest. The PIs have demonstrated success in the growth of InSb quantum wells, as evidenced by ballistic transport over distances of 0.5um at temperatures as high as 185K. The approach has four components: 1)Energy splittings will be probed using an electron spin resonance technique. By varying quantum well structural parameters, factors that influence the Rashba effect will be identified. This is expected to contribute to a more complete understanding of the Rashba and Dresselhaus splittings with the goal of optimizing structures for large zero-field splitting. 2)The large Rashba and Dresselhaus mechanisms are predicted to have interesting consequences in electron focusing experiments. The separate trajectories for electrons with different spin projections will be studied via spin filters based on magnetic focusing. 3)Point-contact techniques for studying spin splitting will be studied. In these one-dimensional channels spin-orbit effects are predicted to lead to much richer conductance spectra. InSb is well suited to this study due to both the large Rashba term and the small effective mass that leads to large confinement energies. 4)Magneto-optical experiments on anti-crossings between Landau levels with opposite spin and on bilayer systems will provide further insight into spin interactions and novel electronic states. These studies are made possible by advances in the materials science of InSb-based heterostructures. Proposed improvements to the heterostructure design will be guided by transmission electron microscopy studies of crystalline defects, which are an important factor limiting the electron mobility and mean free path. Defect densities will be reduced through modification of the buffer layers used on GaAs substrates and through the use of InSb substrates. With the proposed improvements, ballistic transport will persist to longer lengths and higher temperatures. NON-TECHNICAL EXPLANATIONThe project addresses fundamental materials research with strong technological relevance to electronics and photonics, and effectively integrates research and education. The research goes beyond its relevance to developing technologies that exploit spin properties. Research will be integrated with education at various levels. Outreach efforts include the development and implementation of a module on magnetism for use with K-5 students. The curriculum for engineering and physics majors will be improved by the introduction of spintronics as a special topic in two courses. Finally, this research effort will enlist the participation of numerous undergraduates and graduate students. Members of underrepresented groups, particularly women, will continue to be integral to the research.

技术解释 该项目探讨了InSb异质结构中的自旋特性和量子效应，旨在优化依赖于这些现象的应用程序的结构。近年来，专注于半导体中电子自旋性质的实验数量大幅增加。这一努力的大部分动机是利用自旋极化电流的新型设备的愿景。许多挑战仍然存在，包括找到最有效的材料和配置的自旋注入和自旋操纵，并开发一系列的技术来表征自旋特性。一些装置的弹道运输要求带来了额外的挑战。窄带隙材料是一种有前途的解决方案，因为由Rashba、Dresselhaus和Zeeman能量项引起的大自旋效应与窄带隙相关。由于InSb具有任何III-V族半导体中最小的带隙，因此自旋效应预计是最大的。PI已被证明在InSb量子威尔斯的生长中是成功的，正如在高达185 K的温度下在0.5 μ m的距离上的弹道输运所证明的那样。 该方法有四个组成部分：1）将使用电子自旋共振技术探测能量分裂。通过改变量子阱结构参数，将确定影响Rashba效应的因素。预计这将有助于更全面地了解Rashba和Dresselhaus分裂，目标是优化大零场分裂的结构。2)大Rashba和Dresselhaus机制预测有有趣的后果，在电子聚焦实验。将通过基于磁聚焦的自旋过滤器研究具有不同自旋投影的电子的单独轨迹。3）研究自旋分裂的点接触技术。在这些一维通道的自旋轨道效应的预测，导致更丰富的电导谱。锑化铟是非常适合这项研究，由于大的Rashba长期和小的有效质量，导致大的限制能量。4）自旋相反的朗道能级之间的反交叉和双层系统的磁光实验将提供对自旋相互作用和新电子态的进一步了解。 这些研究是可能的InSb基异质结构的材料科学的进步。提出的改进异质结构的设计将指导的晶体缺陷，这是一个重要的因素限制电子迁移率和平均自由path. Defect密度的透射电子显微镜研究将通过修改GaAs衬底上使用的缓冲层，并通过使用InSb衬底减少。随着拟议的改进，弹道运输将持续更长的长度和更高的温度。非技术解释该项目致力于基础材料研究，与电子和光子学具有很强的技术相关性，并有效地整合了研究和教育。这项研究超越了它与开发利用自旋特性的技术的相关性。研究将与各级教育相结合。外联工作包括开发和实施一个供K-5学生使用的磁性单元。通过在两门课程中引入自旋电子学作为专题，改进工程和物理专业的课程设置。最后，这项研究工作将争取许多本科生和研究生的参与。代表性不足群体的成员，特别是妇女，将继续成为研究的组成部分。