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

本课题研究了用于原位沉积薄膜超导体的异质结衬底--GaAs/Al0.3Ga0.7的量子点器件的制备和性能研究。将测试两种几何结构，一种是超导体和二维电子气/量子点之间的电容耦合，另一种是通过隧道势垒的直接耦合。最初的实验将集中在耗散在减少超导体-绝缘体转变附近的位相波动方面的作用，特别是在具有不同长度无序尺度的薄膜中。传统的超导测量涉及宏观探测器，这些探测器平均测量整个样品的性质。中尺度结构提供了在量子效应占主导地位的长度尺度上探测材料的独特能力。耦合的超导体-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。%这是根据妇女在研究和教育中的职业机会(POWRE)计划提供的研究增强补助金。POWRE资助创造了一个机会，可以启动一个重要的研究项目，而这个项目在PI的母校--米德尔伯里学院--是不可行的。获得哈佛大学最先进的设施和介观物理和超导方面的专家的研究人员，将使设备的开发和初步测试成为可能，这些设备将成为未来在米德尔伯里进行的实验的基础。该项目将为终身教职前休假年提供支持。在此期间，PI将为一个重要的研究计划奠定基础，该计划将导致知识的进步，并构成学生教育的研究组成部分。预计这项研究将在与超导材料的行为特别相关的基础水平上贡献基本的材料科学知识，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).***