Local and Non-local Magnetic Moments in Semiconductors

半导体中的局部和非局部磁矩

• 批准号: 0509184
• 负责人: Frances Hellman
• 金额: --
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-10-01 至 2006-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0509184&HistoricalAwards=false
• 关键词: Local; Non; local; Magnetic; Moments

This individual investigator award will provide support for a project that will investigate the effect of adding magnetic moments to semiconductors. Amorphous Si, Ge, and C doped with magnetic ions such as rare earth elements and Mn will be prepared and their electronic, magnetic, thermodynamic, and structural properties measured. The influence of the phonon stiffness and the semiconductor band gap on these properties will be determined. The interaction between these added local moments and the spontaneous moments formed at the Metal-Insulator transition as electrons localize will be studied. The research will provide a phenomenological underpinning for a microscopic model for the three dimensional Metal-Insulator transition, and an understanding of the effect on both transport and magnetic properties of introducing local magnetic moments into a semiconductor. The project will provide research training and education for two graduate students and an estimated 5-6 undergraduates, including exposure to industry through the PI's connections with the Center for Magnetic Recording Research at UCSD and to two National Labs, the National High Magnetic Field Lab and Los Alamos.Magnetic moments play a crucial role in many materials (e.g. the high Tc superconductors and the colossal magnetoresistance manganites). It is known that adding magnetic moments to semiconductors produces effects that are extremely large, but these effects are not well understood. In particular the change in the electrical resistance when such a material is placed in a magnetic field (magnetoresistance) can be enormous. This project will investigate the effect of adding magnetic moments to semiconductors. Samples of amorphous Si, Ge, and C doped with magnetic ions such as rare earth elements and Mn will be prepared. Their electronic, magnetic, thermodynamic, and structural properties will be measured over a wide range of temperature, magnetic field, and doping levels. The research will attempt to determine the principles governing the large effect of magnetic moments in amorphous semiconductors. An increased understanding of these effects may point the way to making the very large magnetoresistance of use to the developing spin electronics technology. In addition this research may increase our understanding of why magnetic moments play such a crucial role in other materials of current interest. The project will provide research training and education for two graduate students and an estimated 5-6 undergraduates, including providing them with an exposure to industry and to the national labs through the PI's collaborations. Thus, they will be well prepared for future careers in academia, or industrial or government laboratories.

该个人调查员奖将为一个项目提供支持，该项目将研究向半导体添加磁矩的效果。将制备用磁化离子（例如稀土元素和MN）掺杂的无定形Si，GE和C，并测量其电子，磁性，热力学和结构特性。将确定声子刚度和半导体带隙对这些性质的影响。这些添加的局部力矩与在金属 - 绝缘体过渡时形成的自发力矩之间的相互作用将被研究。这项研究将为三维金属 - 绝缘体跃迁的微观模型提供一个现象学的基础，并了解将局部磁矩引入半导体的运输和磁性的影响。该项目将为两名研究生提供研究培训和教育，并估计有5至6名本科生，包括通过PI与UCSD的磁性记录研究中心和两个国家实验室（国家高磁场实验室和Los Alamos.Magnetic Moments.Magnetic Moments）在许多材料中起着至关重要的作用（例如，Man the Man ancermanter and Collose and colorsist and colorsist and colorsist and colorsist and colorsiss and collessist and composity and commanters and compocters and compocters and the National High Maginate Field Lab。众所周知，在半导体中添加磁矩会产生极大的效果，但是这些效果尚不清楚。特别地，当将这种材料放置在磁场（磁场抗性）中时，电阻的变化可能是巨大的。该项目将研究向半导体添加磁矩的效果。将制备用磁离子（例如稀土元素和Mn）掺杂的无定形Si，GE和C的样品。它们的电子，磁性，热力学和结构特性将在广泛的温度，磁场和掺杂水平上进行测量。该研究将尝试确定磁性力矩在无定形半导体中的巨大影响的原理。对这些影响的越来越多的理解可能指向开发旋转电子技术的使用极大的磁性磁性。此外，这项研究可能会增加我们对磁矩为何在当前感兴趣的其他材料中发挥如此关键作用的理解。该项目将为两名研究生提供研究培训和教育，估计有5 - 6名本科生，包括通过PI的合作为他们提供行业和国家实验室。因此，他们将为学术界或工业或政府实验室的未来职业做好充分的准备。