Novel Electronic Phases in Two Dimensions

该个人研究者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所表现出的众多强相关相。近年来，这一科学领域表现出了惊人的活力，有了许多惊人的发现。例如，由两个平行的二维电子气体组成的系统，如果两层距离足够近，就可以凝聚成一种奇异的超流体状态。这种“激子玻色凝聚物”将是该项目的重点。需要回答的一个重要问题是，这种半导体系统是否能表现出超导中常见的约瑟夫森效应。低维半导体系统不寻常性质的第二个引人注目的例子是最近在某些掺杂锰的化合物中发现的铁磁性。将进行旨在阐明mn掺杂II-VI半导体（例如ZnCdSe）量子阱的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和本科生的培养以及博士后的培养有很大的帮助。他们将学习为学术、工业或政府研究工作做好准备的技能。该个人研究者奖将支持一个在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行为的理解。最令人感兴趣的话题是那些不能从现在存在的单个电子的特性的详细理解中直接推断出这种集体行为的话题。某些材料中的超导现象可能是这种“涌现”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了一个非凡的新的物质集体相，这将是这个项目的主要焦点。此外，磁性半导体的特性将形成另一个焦点。人们对这种材料的浓厚兴趣源于一种被称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，将为这些年轻科学家在国家技术基础中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.