Probing Superconducting Fluctuations on Mesoscopic Scales: Conductance Fluctuations and Oscillations, and Electron Tunneling

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Non TechnicalThe rapid miniaturization of electronics to the sub-micrometer scale and the resulting vast increase in the capability of computers has been a driving engine for scientific, technological, and economic progress in the past few decades. The foundation of this revolution in information technology is our understanding of how electrons conduct in solid state materials. The goal of this project is to further extend the experimental investigation of electron conduction to nano-sized samples and device elements. This project will search for exotic conductance fluctuations and oscillations in such samples, which will impact on our understanding of electron transport on nanosized length scales. This project will also investigate unique methods for the fabrication and integration of nanosized device elements by a combination of "top-down" electron-beam lithography and "bottom-up" template nanofabrication. The goal is to search for new materials, new physical principles, and new fabrication techniques for the next generation of electronic devices. In addition to training post-docs and graduate students, this project will attract undergraduates (one currently supported) and students from under-represented groups (one currently supported) to pursue cutting-edge scientific research. Such efforts will help to increase the number of graduate students who intend to pursue teaching and research careers, which is critically important for maintaining the vitality of science and technology of this nation.Technical This project will investigate correlation effects in metallic and superconducting ultrathin films, nanowires, and nanotubes. These mesoscopic or nanosized samples are fabricated by either a "top-down" approach based on electron-beam lithography, or a "bottom-up" approach based on template nanofabrication, or a combination of the two. Transport and tunneling experiments will be performed to probe conductance fluctuations, oscillations, and the Josephson tunneling in these samples. These experiments will reveal the important roles that correlation and localization play in the superconductor-insulator quantum phase transition. These experiments will also search for conductance fluctuation and oscillation behavior in metallic (or superconducting) nanotubes of diameters significantly smaller than the phonon dephasing length (or the Ginzburg-Landau coherence length), and in thin films above the spin-paramagnetic limit. Nanofabrication methods developed in this research will impact on emerging fields of nano science and technology. In addition to training post-docs and graduate students, this project will attract undergraduates (one currently supported) and students from under-represented groups (one currently supported) to pursue cutting-edge research. Such efforts will help to increase the number of graduate students who intend to pursue teaching and research careers, which is critically important for maintaining the vitality of science and technology of this nation.