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

技术：本项目旨在通过随温度变化的椭圆偏振光谱(SE)来研究III-V磁性半导体的电、光和磁性质之间的相互作用。虽然大多数其他实验都在探索III-V磁系统的一种特殊性质，但由于SE能够探测材料的电子能带结构，这项研究计划全面揭示各种性质的相互作用。尽管目前基于室温的SE被广泛使用，但这种方法无法充分观察III-V磁系统的相互作用，促使这项工作将SE扩展到4K到300K之间的温度范围。这项技术将具体解决以下与III-V磁性系统有关的问题；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-声子动力学在影响铁磁性方面的意义是什么？此外，还将深入研究金属到绝缘体的转变和铁磁到顺磁的转变的细节。在这些方面获得的见解不仅将加深我们对III-V磁性半导体基础物理的理解，而且将有利于应用科学家实现基于自旋的电子学。非技术性：该项目将极大地促进科学研究和物理专业的研究培训，从而影响学生攻读更高的学位。这是通过将与光学相关的实验整合到几门物理课程中，将所有物理专业的学生引入这些领域，从而增加人才和进入科技劳动力的学生数量。此外，鉴于凯尼恩物理专业的女性比例相当高，这项工作将对少数群体产生强烈影响，特别是女性。让高中生参与基于视频的力学实验，将使他们接触到教室外的现实和课堂内学到的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融入教学：(I)设计一个与磁性半导体和自旋电子学有关的研讨会课程；(Ii)在光学和高级实验课程中加入四个与经典光学和磁光有关的实验；(Iii)为高中生制定一个推广方案，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.