Collaborative Research: Study of Novel Phases in Two Dimensional Electron Systems in High Magnetic Fields and Low Temperature

合作研究：高磁场和低温下二维电子系统新相的研究

• 批准号: 0129652
• 负责人: Sergey Kravchenko
• 金额: --
• 依托单位: Northeastern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-01 至 2005-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0129652&HistoricalAwards=false
• 关键词: Collaborative; Research; Study; Novel; Phases

This Collaborative Research Project will continue experiments that may be evidence for a metal-insulator (M-I) transition in two-dimensional systems of electrons in semiconductors. The M-I transtion has been thought by many to be forbidden on general theoretical grounds. The data, which are suggestive of a M-I transition, remains a mystery despite a growing number of theoretical and experimental papers on the subject. Important recent progress, made by two experimental groups involved in the present project, has shown that the M-I transition in silicon inversion layers may be connected with a ferromagnetic instability in two dimensions. To test this intriguing possibility, magnetoresistance measurements will be performed at ultra-low temperatures and high magnetic fields at the MicroKelvin facility of the NSF-supported National High Magnetic Field Laboratory at Gainesville, Florida. The information sought will be crucial for the understanding of the nature of the enigmatic behavior observed in the two-dimensional electron gas systems. Graduate and undergraduate students participating in this project will receive training in a complex and important area of forefront physics involving cutting edge technology and semiconductor device structures. This will prepare them for a range of careers in industry, government or education.This Collaborative Research Project will investigate the properties of very high purity semiconductor materials in a MOSFET structure somewhat related to those found in many current electronic devices. Contrary to the widely-held expectation that no metallic phase is possible in such two dimensional semiconductors, experimental evidence has been obtained in the last few years that indicates there may be a transition from insulating to metallic behavior. The issue remains unresolved despite a growing number of theoretical and experimental papers on the subject, and poses a serious challenge to our understanding of the behavior of electrons in semiconductors. The principal investigators of the present project have been leading contributors to this field, and have independently obtained recent evidence that the metal-insulator transition may be associated with a tendency toward a ferromagnetic transition. To test this intriguing possibility, measurements will be performed at ultra-low temperatures and high magnetic fields at the MicroKelvin facility at NSF-supported National High Magnetic Field Laboratory at Gainesville, Florida. Gainesville, Florida. The information obtained is expected to be crucial for the understanding of the nature of the enigmatic behavior observed in two dimensional semiconductors. Graduate and undergraduate students participating in this project, including some minority students, will receive training in a complex and important area of forefront physics involving cutting edge technology, including semiconductor device structures This will prepare them for a range of careers in industry, government or education.

这个合作研究项目将继续实验，可能是一个金属-绝缘体（M-I）过渡的证据，在二维系统的电子在半导体。 M-I跃迁被许多人认为在一般的理论基础上是禁止的。 这些数据暗示着M-I跃迁，尽管关于这个主题的理论和实验论文越来越多，但仍然是一个谜。 本项目的两个实验组最近取得的重要进展表明，硅反型层中的M-I转变可能与二维铁磁不稳定性有关。 为了测试这种有趣的可能性，磁阻测量将在超低温和高磁场下进行，在美国国家科学基金会支持的国家高磁场实验室在盖恩斯维尔，佛罗里达的MicroKelvin设施。 所寻求的信息对于理解二维电子气系统中所观察到的神秘行为的本质至关重要。 参与该项目的研究生和本科生将接受涉及尖端技术和半导体器件结构的前沿物理学的复杂和重要领域的培训。 这将为他们在工业，政府或教育领域的职业生涯做好准备。这个合作研究项目将调查MOSFET结构中的超高纯度半导体材料的特性，这些材料与当前许多电子器件中的材料有些相关。 与普遍认为在这种二维半导体中不可能存在金属相的预期相反，在过去几年中已经获得了实验证据，表明可能存在从绝缘到金属行为的转变。 尽管关于这个问题的理论和实验论文越来越多，但这个问题仍然没有得到解决，并对我们理解半导体中电子的行为提出了严峻的挑战。 本项目的主要研究人员一直是这一领域的主要贡献者，并独立获得了最近的证据表明，金属-绝缘体转变可能与铁磁转变的趋势有关。 为了测试这种有趣的可能性，测量将在超低温和高磁场下进行，在美国国家科学基金会支持的国家高磁场实验室在盖恩斯维尔，佛罗里达的MicroKelvin设施。盖恩斯维尔，佛罗里达。 所获得的信息预计是至关重要的理解的性质，在二维半导体中观察到的神秘的行为。 参与该项目的研究生和本科生，包括一些少数民族学生，将在涉及尖端技术的前沿物理学的复杂而重要的领域接受培训，包括半导体器件结构，这将为他们在工业，政府或教育领域的职业生涯做好准备。