Inhomogeneous Charge Dynamics in Strongly Correlated Systems near the Conductor-Insulator Transition

****非技术摘要****在许多具有潜在重大技术重要性的材料中，例如高温超导体，导电状态是通过化学掺杂其他绝缘材料而产生的。 因此，通过改变参数，人们能够将一种材料从导电材料变为不导电材料（绝缘体），反之亦然。了解这种导体-绝缘体转变的本质是材料科学和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。 此外，许多研究表明，接近导体-绝缘体转变的系统和各种玻璃材料的系统的行为具有惊人的相似性，对此的理解也提出了物理学中最深刻和最有趣的问题之一。 许多不同类型的材料都表现出玻璃态行为，包括窗玻璃、掺杂磁性杂质的金属、聚合物、凝胶等，所有这些材料都具有广泛的当前和潜在应用。 该奖项支持一个项目，该项目将通过对半导体器件和高温超导体材料进行电传输和噪声测量来解决导体-绝缘体转变附近复杂的玻璃态行为问题。 预期的结果有望为这些问题提供基本的见解，并且可能与未来的应用相关。 该项目将为研究生和本科生在学术界、工业界和政府的职业生涯提供良好的准备。****技术摘要****该奖项支持一个项目，该项目将解决凝聚态物理中的两个重大科学挑战：i）复杂的现象如何从简单的成分中产生？ ii) 远离平衡会发生什么？为什么？ 特别是，许多强相关的电子材料在从绝缘态到导电态的转变附近表现出复杂、不均匀的行为。 失衡动力学很可能是这种新兴复杂性的确凿证据。 该项目将通过对两种材料的电荷动力学进行全面的比较研究来解决导体-绝缘体转变附近的复杂性问题：半导体异质结构中的二维系统和轻掺杂铜酸盐。 实验将涉及传输与低频动态响应测量相结合。 精心设计的比较研究将能够将更普遍的行为与材料特定的行为区分开来，从而确定开发成功的理论模型所需的主要成分。 该项目将支持研究生和本科生的教育和培训，他们将获得宝贵的技术和分析技能，以适应学术、工业或政府环境中科学技术领域的广泛职业。 PI 和研究生还将参加各种外展活动，例如国家强磁场实验室的年度开放日。

****NON-TECHNICAL ABSTRACT****In many materials with potentially great technological importance, such as high temperature superconductors, the electrically conducting state is created by chemically doping an otherwise insulating material. Therefore by varying a parameter, one is able to change a material from one that conducts electricity to one that does not (an insulator) and vice versa. Understanding the nature of this conductor-insulator transition represents an important issue for materials science and technology. It also presents a fundamental problem in condensed matter physics. Furthermore, many studies have shown striking similarities in the behavior of systems close to a conductor-insulator transition and those of various glassy materials, the understanding of which also presents one of the deepest and most interesting problems in physics. Glassy behavior is exhibited by many different types of materials, including window glasses, metals doped with magnetic impurities, polymers, gels, etc., all of which have a wide range of current and potential applications. This award supports a project that will address the problem of complex, glassy behavior near the conductor-insulator transition by performing electrical transport and noise measurements on semiconductor devices and high temperature superconductor materials. The anticipated results are expected to provide a fundamental insight into these problems, and may be of relevance for future applications. The project will give graduate and undergraduate students an excellent preparation for careers in academia, industry, and government.****TECHNICAL ABSTRACT****This award supports a project that will tackle two of the grand scientific challenges in condensed matter physics: i) How do complex phenomena emerge from simple ingredients? and ii) What happens far from equilibrium and why? In particular, many strongly correlated electronic materials exhibit complex, inhomogeneous behavior near the transition from an insulating into a conducting state. The out-of-equilibrium dynamics may very well be the smoking gun manifestation of this emerging complexity. This project will address the problem of complexity near the conductor-insulator transition by carrying out a comprehensive, comparative study of charge dynamics in two types of materials: two-dimensional systems in semiconductor heterostructures and lightly doped cuprates. The experiments will involve transport combined with low-frequency dynamical response measurements. The carefully designed comparative study will make it possible to separate out the more universal behavior from the material specific one, and thus identify the main ingredients necessary for the development of successful theoretical models. This project will support the education and training of graduate and undergraduate students, who 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. The PI and graduate students will also engage in a variety of outreach activities, such as the Annual Open House at the National High Magnetic Field Laboratory.