Ferromagnetic Semiconductor Nanostructures

铁磁半导体纳米结构

• 批准号: 0305360
• 负责人: Don Heiman
• 金额: $ 33万
• 依托单位: Northeastern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0305360&HistoricalAwards=false
• 关键词: Ferromagnetic; Semiconductor; Nanostructures

This project addresses materials issues relevant to the the hybridization of conventional electronics with ferromagnetic materials, candidates for enhancing present information storage devices, as well as providing ingredients for novel electronic-like devices based on spin injection and spin manipulation (spintronics). The objective of the proposed work is to synthesize novel ferromagnetic semiconductor nanostructures in order to gain fundamental understanding of their magnetic, transport, and optical properties. Goals include: (i) comprehensive understanding of the magnetism and its relation to the semiconducting properties; (ii) higher Curie temperatures; and (iii) improved optical properties. Novel materials and structures of III-V ferromagnetic semiconductors will be synthesized in Northeastern's MBE facility. A primary focus is the exploration of transition metal ions other then Mn, beginning with Cr, but also to improve Mn containing materials. Several theoretical and experimental studies indicate that Cr in III-V materials has the potential for high Curie temperatures. The PI's group has been growing (Ga,Cr,Mn)As for about one year and has recently discovered transition temperatures as high as 700 K. Bandgap engineering will be used to facilitate the investigation of the dependence of electronic energy levels of magnetic ions. For example, Cr has an acceptor-like transition that is midgap in GaAs. By alloying antimony with arsenic, the acceptor energy can be reduced to a level comparable to Mn in GaAs. Varying the energy level of magnetic ions is important for testing and developing theoretical models of ferromagnetism in semiconductors. Magnetic and transport experiments will be used to examine the interaction between the semiconductor carriers and Cr ions. Quantifying this interaction is important for elucidating the coupling within and between magnetic polarons observed in the magnetization of (Ga,Cr)As and the carrier localization effects observed in transport measurements. %%% This project addresses basic materials research issues in a topical area of materials science with significant technological relevance, and places emphasis on the integration of research and education. The research program provides excellent opportunities for hands-on experience in the use of sophisticated scientific equipment. Graduate and undergraduate students will be involved in the design, synthesis, characterization, and science of nanostructured materials. The broad resources, and collaborative aspects, provide special opportunities for education and training of graduate and undergraduate students involved in interdisciplinary forefront research. ***

该项目解决了与传统电子学与铁磁材料的杂交相关的材料问题，用于增强现有信息存储器件的候选材料，以及基于自旋注入和自旋操纵（自旋电子学）的新型类电子器件的成分。所提出的工作的目标是合成新型铁磁半导体纳米结构，以获得其磁性，输运和光学性质的基本了解。目标包括：（i）对磁性及其与半导体性质的关系的全面理解;（ii）更高的居里温度;以及（iii）改进的光学性质。III-V铁磁半导体的新材料和结构将在东北大学的MBE设施中合成。主要焦点是探索除Mn之外的过渡金属离子，从Cr开始，而且还改进含Mn材料。一些理论和实验研究表明，铬在III-V族材料具有高居里温度的潜力。PI的小组一直在增长（Ga，Cr，Mn）As约一年，最近发现转变温度高达700 K。带隙工程将被用来促进磁性离子的电子能级的依赖性的调查。例如，Cr具有在GaAs中的中能隙的类受主跃迁。通过将锑与砷合金化，可以将受主能量降低到与GaAs中的Mn相当的水平。改变磁性离子的能级对于检验和发展半导体铁磁性的理论模型是很重要的。磁性和输运实验将被用来检查半导体载流子和Cr离子之间的相互作用。量化这种相互作用是重要的，阐明内和之间的耦合观察到的磁化（Ga，Cr）As和载流子的本地化效应中观察到的运输测量中的磁极化子。该项目解决了材料科学领域的基础材料研究问题，具有重要的技术相关性，并强调研究和教育的一体化。该研究计划提供了良好的机会，在使用先进的科学设备的实践经验。研究生和本科生将参与纳米结构材料的设计，合成，表征和科学。广泛的资源和合作方面，为参与跨学科前沿研究的研究生和本科生的教育和培训提供了特殊的机会。***