Tunneling and Transport in Ordered and Disordered Superconductors

有序和无序超导体中的隧道效应和输运

• 批准号: 9303022
• 负责人: Allen Goldman
• 金额: $ 38.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1997-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9303022&HistoricalAwards=false
• 关键词: Tunneling; Transport; Ordered; Disordered; Superconductors

9303022 Goldman This research investigates the properties of disordered ultrathin films prepared by vapor deposition onto substrates held at liquid helium temperatures. The central focus is on disorder and magnetic-field-induced superconductor-insulator transitions. The physics underlying these transitions will be identified by mapping out the phase diagram in the space of the magnetic field, temperature, and disorder, bu determining critical exponents, and by investigating the transport and magnetotransport properties of the materials. The structures of the films will be investigated in situ via reflection high energy electron diffraction, and scanning tunneling microscopy. These studies will provide information about the nucleation and growth of the films. %%% This research studies the deposition, growth and physical properties of thin films of superconducting materials. Interestingly, the films lose their superconducting properties when a magnetic field is applied to them, and become isulators. The underlying physics of this dramatic change in electrical conductivity is not well understood, and a number of measurements are proposed to reveal important characteristics of the phenomena. The results will be of fundamental interest in the science of superconductivity. Additionally, the workers will investigate the structure and nucleation of the films, to see how the materials morphology relates to the observed properties. ***

小行星9303022 本研究探讨在液氦温度下，以气相沈积法在基板上所制备的无序薄膜的性质。 中心焦点是无序和磁场诱导的超导体-绝缘体转变。 这些转变的物理基础将通过绘制磁场，温度和无序空间中的相图，确定临界指数，并通过研究材料的传输和磁传输特性来确定。 薄膜的结构将通过反射高能电子衍射和扫描隧道显微镜原位研究。 这些研究将提供有关薄膜成核和生长的信息。 本研究主要研究超导材料薄膜的沉积、生长及物理性质。 有趣的是，当施加磁场时，薄膜失去了超导特性，成为绝缘体。 电导率的这种戏剧性变化的基本物理学还没有很好地理解，并且提出了一些测量来揭示这种现象的重要特征。 这些结果将对超导科学具有根本意义。 此外，工作人员将研究薄膜的结构和成核，以了解材料形态与观察到的特性之间的关系。 ***