Interacting Two Dimensional Electron Systems

技术摘要：本基金支持凝聚态物理实验研究，旨在研究二维相互作用的电子物质。这项工作主要集中在两种材料系统上：通过分子束外延生长的基于砷化镓的半导体异质结构和石墨烯（碳原子的单原子层）。几十年来，人们对砷化镓异质结构进行了深入的研究，并在重要的基础物理和无数的技术应用方面取得了巨大的成就。这项资助将进一步研究在高磁场下砷化镓双量子阱中实现的引人注目的激子玻色凝聚，并对激子超流动性的概念进行关键的测试。与砷化镓相比，石墨烯是一种新材料，六年前才被分离出来。石墨烯的出现引发了一场研究风暴，因为它具有潜在的技术应用潜力和显著的基本物理属性。这笔拨款使人们能够对石墨烯进行一系列新的实验，重点是研究其热力学和热电性质。特别是，将测量狄拉克准粒子在石墨烯中的能量弛豫率，并制造一种新型的石墨烯热载子热电偶。这项资助的研究将对研究生、本科生和博士后的教育做出巨大贡献。摘要：本基金支持先进半导体材料和石墨烯（碳的单原子层）的基础研究。其目的是提高对这种材料中大量电子行为的理解。最令人感兴趣的主题是那些不能从对单个电子性质的详细了解中直接推断出这种集体行为的主题。这样的调查远非单纯的学术活动。一百年前，超导性是在如此低的温度下被发现的，以至于有实际头脑的市民一定认为它是一种无用的好奇心。如今，超导性被认为通过使磁共振成像（MRI）成为可能，已经彻底改变了医学诊断。这笔拨款允许对一种奇异形式的量子物质进行实验，这种物质被称为激子凝聚体，其性质与超导体相似。这种类比有多接近仍是一个关键问题。该基金还支持石墨烯热性能的实验。这种新材料为基础和应用上的新发现提供了极好的前景。这项资助的研究由研究生和本科生以及一名研究生助理进行。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。

Technical Abstract: This grant supports experimental condensed matter physics research aimed at the study of interacting electronic matter in two dimensions. The work focuses on two material systems: gallium arsenide-based semiconductor heterostructures grown by molecular beam epitaxy and graphene, a single atomic layer of carbon atoms. GaAs heterostructures have been intensely studied for several decades, and have yielded a vast trove of important fundamental physics and myriad technical applications. This grant enables further investigation of the remarkable excitonic Bose condensate which is realized in GaAs double quantum wells at high magnetic field, and crucial tests of the concept of excitonic superfluidity will be performed. In contrast to GaAs, graphene is quite new, having been isolated only six years ago. The advent of graphene sparked a firestorm of research owing to both its potential for technological application and its remarkable fundamental physics attributes. The grant enables a new set of experiments on graphene which focus on its thermodynamic and thermoelectric properties. In particular, the energy relaxation rates of the Dirac quasiparticles in graphene will be measured and a novel graphene hot-carrier thermocouple will be fabricated. The research enabled by this grant will contribute greatly to the education of graduate and undergraduate students and a postdoctoral associate. Non-technical Abstract: This grant supports basic research on advanced semiconductor materials, and on graphene, a single atomic layer of carbon. The aim is to improve the understanding of how large collections of electrons behave in such materials. 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. Such investigations are far from mere academic exercises. One hundred years ago superconductivity was discovered at such low temperatures that practically-minded citizens must have regarded it as a useless curiosity. Nowadays superconductivity is recognized to have revolutionized medical diagnostics by enabling magnetic resonance imaging (MRI). This grant allows experiments on an exotic form of quantum matter, known as an exciton condensate, whose properties resemble those of superconductors. How close the analogy is remains a key question. The grant also support experimentation on the thermal properties of graphene. This new material offers excellent prospects for new discoveries of both fundamental and applied significance. The research funded by this grant is 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.