RUI: Probing the Interplay between Magnetic Properties, Band Structure and Carrier Dynamics of III-V-based Magnetic Semiconductors

技术方面：本项目是利用依赖温度的椭圆偏振光谱（SE）研究III-V型磁性半导体的电子、光学和磁性的相互作用。虽然大多数其他实验探测III-V磁系统的特定性质，但由于SE能够探测材料的电子带结构，因此该研究计划全面揭示各种性质的相互作用。虽然基于室温的SE目前被广泛使用，但该方法无法充分观察III-V磁系统的相互作用，这促使本工作将SE扩展到覆盖4K到300K之间的温度范围。该技术将具体解决与III-V磁系统相关的以下问题；交换和杂化相互作用如何微调磁耦合；杂质带对磁性和导电性的影响是什么？载流子-声子动力学对铁磁性的影响有何意义？此外，金属到绝缘体转变和铁磁到顺磁转变的细节将被深入研究。在这些方面获得的见解不仅将加深我们对III-V磁性半导体基本物理的理解，而且还将使应用科学家实现基于自旋的电子学。非技术性：本项目将显著促进物理专业学生的科学研究和科研训练，进而影响学生继续深造。这是通过将光学相关的实验纳入几门物理课程，所有物理专业的学生都将被引入这些领域，从而增加人才和学生进入科技队伍。此外，鉴于凯尼恩大学物理学专业的女性比例相当高，这项工作将对少数群体，特别是女性产生强烈影响。让高中生参与基于视频的力学实验将使他们接触到外部现实与课堂所学理论之间的密切联系。该项目将通过以下方式将拟议研究的各个方面整合到教学中：(i)设计与磁性半导体和自旋电子学相关的研讨会课程；（ii）在经典光学和磁光学相关的光学和高级实验课程中注入四个实验；（iii）为高中学生开发一个外联计划，包括基于视频的力学实验。

Technical: This project is to study the interplay of electronic, optical and magnetic properties of III-V magnetic semiconductors via temperature-dependent spectroscopic ellipsometry (SE). While most other experiments probe a particular property of III-V magnetic systems, since SE is capable of detecting the electronic band structure of a material, the study is planning to uncover the interplay of various properties comprehensively. Although room-temperature based SE is widely used presently, that method is incapable of observing the interplay of III-V magnetic systems adequately, motivating this work to extend SE to cover a temperature range between 4K and 300K. This technique will specifically address the following issues related to III-V magnetic systems; how does exchange and hybridization interactions fine tune the magnetic coupling; what is the impact of the impurity bands in affecting magnetism and conductivity; and what is the significance of carrier-phonon dynamics in influencing the ferromagnetism? Additionally, the details of both the metal-to-insulator transition and the ferromagnetic to paramagnetic transition will be investigated thoroughly. Insights gained on these aspects will not only deepen our understanding of the fundamental physics of III-V magnetic semiconductors but also benefit applied scientists implementing spin-based electronics.Non-technical: This project will significantly advance scientific research, and research training among physics majors, which will subsequently influence students to pursue advanced degrees. This is by incorporating experiments related to optics into several physics courses, all physics majors will be introduced to these fields, resulting in the increase in talent and number of students entering the scientific and technical workforce. Also the work will have a strong impact on minority groups, particularly women, in light of the fairly high percentage of women majoring in physics at Kenyon. Engaging high school students on video-based mechanics experiments will expose them to the intimate connection between the realities outside and the theories learnt inside the classroom. The project will integrate various aspects of the proposed research into teaching by: (i) designing a seminar course related to magnetic semiconductors and spintronics; (ii) injecting four experiments into Optics and Advanced Lab courses related to classical optics and magneto-optics; (iii) developing an outreach program for high school students involving video-based mechanics experiments.