A Dual Tip STM for Imaging the Superconducting Phase Difference

ORAL

Abstract

We have built a dual tipped millikelvin STM with each tip capable of independently scanning a sample. We will use the STM to measure spatial variations of the gauge-invariant phase difference at the atomic scale. The two tips along with the superconducting sample constitute a SQUID. This configuration is designed to minimize fluctuations in the superconducting phase of one of the tips as it scans the sample, hence inhibiting supercurrent suppression. We are currently developing a technique to fabricate superconducting Niobium tips for use with this system.

*This project was funded in part by NSF and the Laboratory for Physical Sciences

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Authors

  • Anita Roychowdhury

    • Laboratory for Physical Sciences and Physics Dept., University of Maryland, College Park

  • M.A. Gubrud

    • Department of Physics and Astronomy, University of North Carolina, Chapel Hill

  • D. Sullivan

    • NASA - Goddard

  • Michael Dreyer

    • Laboratory for Physical Sciences and Physics Dept., University of Maryland, College Park
    • University of Maryland

  • J. R. Anderson

    • Physics Dept., University of Maryland, College Park

  • C.J. Lobb

    • Physics Dept., University of Maryland, College Park

  • F.C. Wellstood

    • Physics Dept., University of Maryland, College Park
    • University of Maryland
    • JQI, CNAM, Department of Physics, University of Maryland
    • JQI, CNAM, Dept. of Phys, Univ of MD, College Park