Novel Electronic Phases in Two Dimensions

这一个人研究人员奖将支持实验凝聚态物理研究，旨在研究半导体异质结构中二维电子系统表现出的众多强关联相。近年来，这一科学领域显示出了非凡的生命力，有了一些非常惊人的发现。例如，如果两层足够接近，由两个平行的二维电子气形成的系统可以凝聚成奇异的超流状态。这种“激子玻色凝聚体”将是该项目的重点。一个需要回答的重要问题是，这个半导体系统是否会表现出超导电性中常见的约瑟夫森效应。低维半导体系统不寻常特性的第二个戏剧性例子是最近在某些锰掺杂化合物中发现的铁磁性。本课程将进行旨在阐明掺锰II-VI半导体(如：锌镉镉)量子阱基本物理性质的实验。特别是，将使用一种新的量子隧道技术来研究这种系统的自旋极化。这项研究将对研究生、本科生和博士后研究生的培养有很大的帮助。他们将学习为学术、工业或政府研究事业做准备的技能。这一个人研究人员奖将支持一个处于先进半导体材料基础研究前沿的项目。这项研究的目的是提高对大量电子集合行为的理解。最感兴趣的主题是那些不能从对目前存在的单个电子的性质的详细了解中直接推断出这种集体行为的主题。某些材料中的超导现象可能是这种“新兴”现象的最著名的例子，但还有许多其他的例子。这里支持的工作将集中在半导体中所谓的“二维”电子系统中出现的现象的例子。一个特别有趣的例子是，两个平行的电子层相互作用，形成一个引人注目的新的集体物质相，这将是这个项目的主要焦点。此外，磁性半导体的性质将形成另一个焦点。人们对这种材料的浓厚兴趣源于一种名为自旋电子学的先进新技术的愿景。大部分研究将由研究生和本科生以及一名研究生助理执行。因此，该项目具有很强的教育成分，并将为这些年轻科学家在国家技术基础内从事复杂的工作做好准备。

This individual investigator award will support experimental condensed matter physics research aimed at the study of the numerous strongly correlated phases that are exhibited by two-dimensional electron systems in semiconductor heterostructures. This field of science has shown remarkable vitality in recent years, with a number of very striking discoveries. For example, a system formed of two parallel two-dimensional electron gases can condense into an exotic superfluid state if the two layers are close enough together. This "excitonic Bose condensate" will be a focus of the project. An important question to be answered is whether this semiconductor system can exhibit the Josephson effect familiar from superconductivity. A second dramatic example of the unusual properties of low dimensional semiconductor systems is the recent discovery of ferromagnetism in certain manganese-doped compounds. Experiments designed to elucidate the basic physical properties of Mn-doped II-VI semiconductor (e.g. ZnCdSe) quantum wells will be undertaken. In particular, the spin polarization of such systems will be studied using a novel quantum tunneling technique. This research will contribute greatly to the education of graduate and undergraduate students and a postdoctoral associate. They will learn skills that prepare them for academic, industrial, or government research careers.This individual investigator award will support a project at the frontier of basic research on advanced semiconductor materials. The aim of this research is to improve the understanding of how large collections of electrons behave. The topics of greatest interest are those in which such collective behavior cannot be directly inferred from the detailed understanding of the properties of individual electrons that now exists. The phenomenon of superconductivity in certain materials is perhaps the best-known example of such an "emergent" phenomenon, but there are many others. The work supported here will concentrate on examples of emergent phenomena in so-called "two-dimensional" electron systems in semiconductors. A particularly interesting example, in which two parallel layers of electrons interact to form a remarkable new collective phase of matter, will be a main focus of this project. In addition, the properties of magnetic semiconductors will form another focus. There is intense interest in such materials stemming from a vision of an advanced new technology called spintronics. Much of the research will be executed by graduate and undergraduate students and a postgraduate associate. Thus this project has a strong educational component and will prepare these young scientists for sophisticated jobs within the Nation's technological base.