Thin Film Diluted Magnetic Semiconductors with Tetradymite Structure

具有辉辉石结构的薄膜稀磁半导体

• 批准号: 0305221
• 负责人: Ctirad Uher
• 金额: $ 38.34万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0305221&HistoricalAwards=false
• 关键词: Thin; Film; Diluted; Magnetic; Semiconductors; Thin; Film; Diluted; Magnetic; Semiconductors

This project explores the simultaneous presence of electronic and spin degrees of freedom in the tetradymite-type A2V B3VI (A=Bi, Sb; B=Te, Se) family of semiconductors. The incorporation of relatively high concentrations of magnetic impurities in tetradymite-type semiconductors, and thus higher Curie temperatures, is sought through thin films of these materials. The project focuses on several objectives: 1) to demonstrate the growth of thin films of Sb2Te3, Bi2Te3, and Bi2Se3 -as well as alloys and superlattices of these binary compounds-doped with transition metals; 2) to explore the upper limits of incorporation of the magnetic impurities (phase diagram) in these hosts; and 3) pursue a comprehensive program of characterization of the structural, magnetic, and transport properties of the obtained DMS (dilute magnetic semiconductor) films. The role of the magnetic impurities in the tetradymite semiconductors and their impact on properties will be studied employing electrical conductivity, magnetoresistance, thermopower, thermal conductivity, specific heat, Hall effect, magnetization, and magnetic susceptibility measurements from temperatures of 2K to 300K and in magnetic fields of 0 to 9 T. The project is expected to advance basic knowledge of diluted magnetic semiconductors and thereby help lay groundwork for future spintronics applications. Since the crystal structure and the magnetic ions utilized in the proposed materials are distinctly different from traditional diluted magnetic semiconductors such as Mn-doped III-V or II-VI compounds, the project may shed new light on fundamental issues of magnetism in semiconductors, and possibly of magnetism generally. The highly anisotropic environment of the tetradymite-type crystal structure with its pronounced octahedral coordination of atoms may play a key role in the development of magnetic order; this is in contrast to the cubic environment of Mn-doped zinc-blende or wurtzite structures with their distinct tetrahedral bonding.%%% This project addresses basic materials and condensed matter physics research issues in a topical area of materials science with technological relevance, and places emphasis on the integration of research and education. Graduate and undergraduate students will be involved in the synthesis, processing, and characterization of electronic/magnetic materials. Training of graduate and undergraduate students in the areas of MBE growth, semiconductor physics, and magnetism provides special opportunities for them in research and education, and a sound investment in the future workforce. The project is jointly supported by the DMR Electronic Materials and Condensed Matter Physics programs.***

该项目探讨了四亚簇型A2V B3VI（a = bi，sb; b = te，se）族的电子自由度的同时存在。通过这些材料的薄膜，寻求了四亚簇型半导体中相对较高的磁杂质的结合，从而掺入了较高的居里温度。该项目侧重于几个目标：1）证明SB2TE3，BI2TE3和BI2SE3的薄膜的生长 - 以及这些二元化合物的合金和超晶格，掺有过渡金属； 2）探索这些宿主中磁杂质（相图）掺入的上限； 3）追求获得的DMS（稀释磁性半导体）膜的结构，磁性和传输特性表征的全面计划。将研究磁杂质在四亚岩半导体中的作用及其对性能的影响，并将使用电导率，磁力，热电器，热电导率，特定的热量，特定的热量，玻璃效应，磁化效果，磁化和磁化率测量的磁性且在磁性障碍中的局部磁性差异。 Spintronics应用。由于所提出材料中使用的晶体结构和磁离子与传统稀释的磁性半导体（例如掺杂MN的IIII-V或II-VI化合物）明显不同，因此该项目可能会对半导体中磁性的基本问题（可能是磁性含量）提供新的启示。四亚簇型晶体结构的高度各向异性环境，其明显的八面体配位原子可能在磁性的发展中起关键作用。这与Mn掺杂的锌醇或Wurtzite结构的立方环境及其独特的四面体键合。%%%;此项目在材料科学的主题领域中涉及基本材料和凝聚的物理学研究问题，其技术科学与技术相关性，并将重点放在研究与教育的融合上。研究生和本科生将参与电子/磁性材料的合成，加工和表征。在MBE增长，半导体物理学和磁性领域的研究生和本科生的培训为研究和教育方面的特殊机会以及对未来劳动力的良好投资提供了特殊的机会。该项目由DMR电子材料和凝结物理计划共同支持。***