Tunneling and Transport in Ordered and Disordered Superconductors

9623477 Goldman The study of two dimensional superconducting films allows access to several important paradigms in contemporary Condensed Matter Physics including the superconductor-insulator transition, the quantum tunneling of vortices, and other quantum properties of Abrikosov vortices. The hallmark of the work is the extension of the parameter space to very low temperatures and very high magnetic fields. The focus of work on the superconductor-insulator transition will be on resolving whether the transition is governed by a variant of the Boson- Hubbard model or, is a consequence of decreased screening by disorder of the repulsive electron-electron interaction. The work on quantum tunneling of vortices should reveal new features of the dynamics of vortices, in particular the extent to which their behavior can be fundamentally quantum mechanical. The other investigations of quantum properties of vortices, including studies of quantum vortex lattice melting, superconducting analogs of the quantum Hall effect, and vortex shot noise will contribute to a coherent picture of electron transport and superconductivity in two dimensions. %%% The study of two dimensional superconductors impacts important paradigms in contemporary Condensed Matter Physics including the superconductor-insulator transition, and the quantum tunneling of vortices, an important dynamical property of Abrikosov vortices. The investigation of model problems and model systems in two dimensions, in addition to their intrinsic scientific interest, will contribute to our knowledge of the mechanism of high-Tc superconductivity, and to our understanding of vortex dynamics. The dynamics of vortices, which exist in superconductors in magnetic fields, are of interest because vortex motion causes dissipation. The promise of superconductivity to bring about changes in electrical and electronic technology is connect ed with reduced dissipation. The understanding of the mechanism of high temperature superconductivity will aid in the search for new materials. The understanding of the fundamental limits on performance resulting from vortex motion will contribute to our understanding of factors which could limit the technological usefulness of superconductors. ***