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

过渡金属和稀土掺杂 Sb2Te3 和 Bi2Te3 稀磁半导体

• 批准号: 0604549
• 负责人: Ctirad Uher
• 金额: --
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0604549&HistoricalAwards=false
• 关键词: Transition; Metal; Rare; Earth; Doped

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.

技术：这个项目寻求新的知识和对Sb2Te3和Bi2Te3中铁磁性状态的更多了解。人们对掺杂这些材料后的磁性知之甚少。本项目的目的是研究：(I)过渡金属(TM)磁性杂质在Sb_2Te_3和Bi2Te_3薄膜中的掺杂上限，(Ii)Tm杂质中心在主体晶格中的性质，以及(Iii)载流子密度对结构磁性状态的影响。超快自旋动力学研究将被用来评估基本相互作用参数，例如控制TM离子和载流子之间以及TM离子本身之间耦合能量的交换积分Jp，d和Jd，d。此外，还将探讨稀土及其部分填充的f轨道对Sb_2Te_3和Bi2Te_3中激发磁相互作用的影响。可以预料的是，由于轨道矩不熄灭，S，p-f交换作用可能更强，这可能导致更高的居里温度，前提是足够的稀土离子可以被掺入到薄膜基质中，并且反铁磁超交换不是太强。非技术性：该项目解决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。这项研究将在基础水平上为潜在的下一代电子/自旋电子器件的新的理解和能力贡献基本的材料科学知识。该计划的一个重要特点是通过在一个具有根本意义和技术意义的领域对学生进行培训，将研究和教育结合起来。该项目为研究生和本科生在具有技术意义的领域提供了丰富的培训基础(分子束外延生长、结构、运输和磁性表征)。这项研究的各个方面将作为定期安排的座谈的一部分呈现给研究生，自旋电子学的主题也被纳入到一门物理入门课程的课程中。该项目由DMR电子材料和凝聚态物理项目共同资助。