POWRE: Quantum Dot Studies of the Two-Dimensional Superconductor-Insulator Transition

本计画系以GaAs/Al 0.3Ga 0.7As异质结构为基底，以原位成长薄膜超导体，制作量子点元件，并研究其特性。两种几何形状将被测试，一个是超导体和二维电子气/量子点之间的电容耦合，另一个是通过隧道势垒直接耦合。最初的实验将集中在减少超导体-绝缘体转变附近的相位波动的耗散的作用，特别是在具有不同长度尺度的无序薄膜。传统的超导测量涉及宏观探针，平均整个样品的属性。中尺度结构提供了独特的能力，探测材料的长度尺度上，量子效应占主导地位。耦合超导体-量子点结构将为分析超导体-绝缘体转变以及改变和研究介观长度尺度上的电子输运提供强有力的手段。这是根据研究和教育领域女性专业机会（POWRE）方案提供的研究增强补助金。POWRE赠款创造了一个机会，启动一个重要的研究项目，这是不可行的，在PI的家乡机构，米德尔伯里学院的整体发展。利用哈佛最先进的设施和介观物理学和超导学方面的专家研究人员，将使设备的开发和初步测试成为可能，这些设备将成为米德尔伯里未来实验的基础。该项目将为任期前休假年提供支助。在此期间，PI将为一个重要的研究计划奠定基础，这将导致知识的进步，并构成学生教育的研究组成部分。该研究有望在与超导材料行为特别相关的基础水平上贡献基础材料科学知识，并有助于研究和教育的整合。该项目由材料研究部和MPS OMA（多学科活动办公室）共同支持。

This project addresses the fabrication and properties study of quantum dot devices formed from GaAs/Al0.3Ga0.7As heterostructure substrates for in-situ deposition of thin film superconductors. Two geometries will be tested, one for capacitive coupling between the superconductor and two-dimensional electron gas/quantum dot, the other for direct coupling through a tunnel barrier. Initial experiments will focus on the role of dissipation in reducing phase fluctuations near the su-perconductor-insulator transition, particularly in films with different length scales of disorder. Traditional superconductivity measurements involve macroscopic probes that average over the properties of an entire sample. Mesoscale structures offer the unique ability to probe materials on length scales at which quantum effects dominate. Coupled superconductor-quantum dot structures will provide a powerful means of both analyzing the superconductor-insulator transition and altering and studying electron transport on mesoscopic length scales. %%% This is a research enhancement grant made under the Professional Opportunities for Women in Research and Education (POWRE) program. The POWRE grant creates an opportunity to initiate a significant research project that is not feasible to develop in its entirety at the PI's home institution, Middlebury College. Access to both state-of-the-art facilities at Harvard and researchers who are experts on mesoscopic physics and superconductivity will make possible the develop-ment and initial testing of devices that will form the basis of future experiments performed at Middlebury. This project will provide support for a pre-tenure leave year. During this time the PI will lay the foundations for a significant research program that will both lead to the advancement of knowledge and constitute the research component of student education. The research is ex-pected to contribute basic materials science knowledge at a fundamental level of special relevance to the behavior of superconducting materials, and to assist with the integration of research and education. The project is co-supported by the Division of Materials Research, and the MPS OMA(Office of Multidisciplinary Activities).***