Spin and Other Electronic Properties of InSb Quantum Wells

本计画针对InSb量子威尔斯中的电子自旋特性与弹道输运效应，并针对依赖于这些现象的应用，来优化这些结构。大的自旋效应，如Rashba和塞曼条款与窄的带隙。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。该方法涉及一系列的实验来研究这些影响InSb异质结。首先，由于Rashba效应的能量分裂将使用电子自旋共振技术进行探测。通过改变量子阱的结构参数，将确定影响Rashba效应的因素。这将有助于更全面地了解Rashba效应，并优化大Rashba分裂的结构。第二，将探索研究一维通道中自旋分裂的点接触技术。在这些一维通道中，Rasbha效应已被预测为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。第三，量子霍尔铁磁体将寻求利用大塞曼效应在InSb。对量子流体中的铁磁性的研究可能会提高对铁磁性的总体理解。最后，一个新提出的自旋过滤器，利用大塞曼效应将被开发。本文将对InSb量子威尔斯阱的弹道输运性质进行实验研究。InSb的小有效质量导致长的平均自由程。初步数据表明，即使在185 K下也会发生弹道传输。虽然与自旋无关，但某些自旋装置需要弹道输运。计划开发在室温下表现出弹道传输的结构和具有足够长的低温平均自由程以进行电子聚焦实验的结构。异质结质量的持续改进将得到正在进行的激子研究的帮助，这些研究提供了对器件设计重要的材料参数值。该项目解决了具有技术相关性的电子材料科学领域的基础研究问题。该项目的一个重要特点是高度重视教育，并将研究与教育相结合。这项研究工作招募的贡献，从本科生，研究生和博士后。这些经验将有助于学生和工作人员在技术重要性领域的就业。PI和两个co-PI之间的合作资源为高度跨学科前沿研究的教育和培训提供了特殊机会。*

This project addresses electron spin properties and ballistic transport effects in InSb quantum wells, and aims to optimize such structures for applications that rely on these phenomena. Large spin effects such as the Rashba and Zeeman terms are correlated with narrow band gaps. Because InSb has the smallest band gap of any III-V semiconductor, spin effects are expected to be amongst the largest. The approach involves a range of experiments to study these effects in InSb heterostructures. First, energy splitting due to the Rashba effect will be probed using an electron spin resonance technique. By varying the structural parameters of the quantum well, factors that influence the Rashba effect will be identified. This is expected to contribute to a more complete understanding of the Rashba effect with the goal of optimizing structures for large Rashba split-ting. Second, point-contact techniques for studying spin splitting in 1D channels will be ex-plored. In these 1D channels the Rasbha effect has been predicted to lead to a much richer con-ductance 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. Third, quantum Hall ferromagnets will be sought by exploiting the large Zeeman effect in InSb. Studies of ferromagnetism in quantum fluids may improve understanding of ferromagnetism in general. Lastly, a newly proposed spin filter that takes advantage of the large Zeeman effect will be developed. Experiments on the bal-listic transport properties of InSb quantum wells will be performed. The small effective mass of InSb leads to long mean free paths. Preliminary data suggests ballistic transport even at 185K. Although unrelated to spin, ballistic transport is required for some spin devices. It is planned to develop structures that exhibit ballistic transport at room temperature and structures that have low-temperature mean free paths sufficiently long for electron focusing experiments. Continued improvement in the quality of heterostructures will be aided by ongoing excitonic studies which provide values of materials parameters important for device design. %%% The project addresses fundamental research issues in areas of electronic materials science having technological relevance. An important feature of the project is the strong emphasis on education, and the integration of research and education. This research effort enlists contributions from un-dergraduates, graduate students, and postdocs. These experiences will contribute to the prepara-tion of students and staff for employment in areas of technologically importance. The combined resources of collaborations among the PI and two co-PIs provide special opportunities for educa-tion and training in highly interdisciplinary forefront research.***