Transition Metal and Rare Earth Doped Sb2Te3 and Bi2Te3 Diluted Magnetic Semiconductors

技术：该项目寻求对Sb 2 Te 3和Bi 2 Te 3铁磁状态的新知识和更好的理解。关于掺杂这些材料的磁性知之甚少。该项目的方法是调查：（i）在Sb 2 Te 3和Bi 2 Te 3薄膜中掺入过渡金属（TM）磁性杂质的上限，（ii）基质晶格中TM杂质中心的性质，以及（iii）载流子密度对结构磁状态的影响。超快自旋动力学研究将用于评估基本的相互作用参数，如交换积分Jsp，d和Jd，d，这些参数决定TM离子和载流子之间以及TM离子本身之间的耦合能。此外，研究稀土及其部分填充的f轨道对Sb 2 Te 3和Bi 2 Te 3中的磁相互作用的影响。可以预期，由于轨道矩没有被淬灭，s，p-f交换相互作用可能更强，这可能导致更高的居里温度，前提是足够的稀土离子可以并入薄膜基质中并且反铁磁超交换不太强。非技术性：该项目涉及具有高度技术相关性的材料科学专题领域的基础研究问题。该研究将在基础层面上为潜在的下一代电子/自旋电子器件的新理解和能力贡献基础材料科学知识。该计划的一个重要特点是通过在一个基本和技术上重要的领域对学生进行培训来整合研究和教育。该项目为具有技术意义的研究生和本科生提供了丰富的培训基础（MBE生长，结构，运输和磁性表征）。这项研究的各个方面作为定期安排的座谈会的一部分，介绍给研究生和自旋电子学的主题被纳入活跃的物理学入门课程的课程。该项目由DMR电子材料和凝聚态物理计划共同资助。

Technical: This project seeks new knowledge and greater understanding of the ferromagnetic state in Sb2Te3 and Bi2Te3. Little is known about the magnetic properties upon doping these materials. The approach of this project is to investigate: (i) the upper limits of incorporation of transition metal (TM) magnetic impurities in thin films of Sb2Te3 and Bi2Te3, (ii) the nature of the TM impurity centers in the host lattice, and (iii) the influence of charge carrier density on the magnetic state of the structure. Ultrafast spin dynamics studies will be used to assess fundamental interaction parameters such as the exchange integrals Jsp,d and Jd,d that govern the coupling energy between the TM ions and carriers, and between TM ions themselves. Additionally, studies of the influence of rare earths and their partially filled f-orbitals on stimulating magnetic interactions in Sb2Te3 and Bi2Te3 will be explored. It is expected, that since the orbital moment is not quenched, the s, p-f exchange interactions may be stronger which could lead to higher Curie temperature provided enough of the rare earth ions can be incorporated in the thin film matrix and antiferromagnetic superexchange is not too strong. Non-Technical: The project addresses basic research issues in a topical area of materials science having high technological relevance. The research will contribute basic materials science knowledge at a fundamental level to new understanding and capabilities for potential next generation electronic/spintronic devices. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. The project provides a rich training ground (MBE growth, structural, transport, and magnetic characterization) for graduate and undergraduate students in areas that have technological significance. Aspects of this research are presented to graduate students as part of regularly scheduled colloquia and the topic of spintronics is incorporated to enliven the curriculum of an introductory physics course. The project is cofunded by the DMR Electronic Materials and Condensed Matter Physics Programs.