Study of Correlated Insulators and Metals in Two Dimensions

该项目将同时解决凝聚态物理的两个主要问题：金属-绝缘体转变和玻璃态行为。最近的研究表明，这两者很可能是密切相关的。这个实验项目的重点将是半导体异质结构中二维系统的性质。在硅中使用二维电子系统要解决的具体问题包括：(1)非平衡态玻璃动力学，(2)库仑相互作用范围对金属-绝缘体转变和玻璃效应的作用，以及(3)局部磁矩对金属-绝缘体转变和玻璃行为的影响。此外，还将探讨其他材料在二维系统中玻璃态冻结的可能性。这些问题将采用交通和噪音测量相结合的方式进行调查。结果应该提供问题的关键方面的信息：无序，电子-电子相互作用，以及自旋和电荷自由度的作用。这将大大有助于我们理解无序的、强相关的系统。在追求这些目标的过程中，本科生、研究生和博士后将获得宝贵的技术和分析技能，以便在学术、工业或政府环境中从事科学和技术领域的广泛职业。在许多具有潜在重大技术重要性的新材料中，例如最近发现的高温超导体，金属态是通过化学掺杂原本绝缘的材料而产生的。因此，这些材料发现自己接近所谓的“金属-绝缘体”过渡。因此，了解金属-绝缘体转变的本质是材料科学与技术的一个重要问题。它还提出了凝聚态物理中的一个基本问题。最近的几项研究表明，接近金属-绝缘体过渡的系统的行为与各种玻璃材料的系统的行为惊人地相似，对这种现象的理解也提出了物理学中最深刻和最有趣的问题之一。这个实验凝聚态物理项目将同时解决金属-绝缘体转变和玻璃态行为的问题，通过结合电输运和噪声测量。这些实验的预期结果有望为这些问题提供一个基本的见解。此外，由于测量将在半导体异质结构上进行，结果可能会对下一代半导体器件的开发产生影响，这些器件将用于新技术领域，例如量子计算和自旋电子学，其中器件噪声可能是限制其性能的主要因素之一。该项目将为博士后研究人员、研究生和本科生在学术界、工业界和政府的职业生涯做好准备。

This project will address simultaneously two major problems of condensed matter physics: The metal-insulator transition and glassy behavior. Recent studies have indicated that the two are most likely intimately related. The focus of this experimental project will be on the properties of two-dimensional systems in semiconductor heterostructures. Specific topics to be addressed using a two-dimensional electron system in Si include: (1) nonequilibrium glassy dynamics, (2) the role of the range of Coulomb interactions on the metal-insulator transition and glassy effects, and (3) the effect of local magnetic moments on the metal-insulator transition and glassy behavior. In addition, the possibility of glassy freezing in two-dimensional systems in other materials will be also explored. These issues will be investigated using a combination of transport and noise measurements. The results should provide information on crucial aspects of the problem: disorder, electron-electron interactions, and the role of spin and charge degrees of freedom. This will contribute significantly to our understanding of disordered, strongly correlated systems. In pursuing these objectives, undergraduate students, graduate students and postdocs will acquire valuable technical and analytical skills for a wide range of careers in the areas of science and technology in academic, industrial or government settings.In many of the novel materials with potentially great technological importance, such as recently discovered high temperature superconductors, the metallic state is created by chemically doping an otherwise insulating material. Such materials, therefore, find themselves close to a so-called "metal-insulator" transition. Understanding the nature of the metal-insulator transition thus represents an important issue for the materials science and technology. It also presents a fundamental problem in condensed matter physics. Several recent studies have shown striking similarities in the behavior of systems close to a metal-insulator transition and those of various glassy materials, the understanding of which also presents one of the deepest and most interesting problems in physics. This experimental condensed matter physics project will address simultaneously both the problem of the metal-insulator transition and that of glassy behavior by using a combination of electrical transport and noise measurements. The results anticipated from these experiments are expected to provide a fundamental insight into these problems. Furthermore, since measurements will be carried out on semiconductor heterostructures, the results may have an impact on the development of next generation semiconductor devices to be used in new technological areas such as quantum computation and spintronics, for example, where device noise may be one of the main factors limiting its performance. The project will give postdoctoral researchers, graduate and undergraduate students an excellent preparation for careers in academia, industry, and government.