A Dual Tip STM for Imaging the Superconducting Phase Difference

ORAL

Abstract

We have built a dual tipped STM, with each tip capable of independently scanning a sample. We will use the STM at ultra-low (mK) temperatures to study superconducting samples. The two tips along with the superconducting sample constitute a SQUID. This configuration is designed to minimize fluctuations in the Josephson phase of one of the tips, which scans the sample, while the other tip acts as a reference junction. Calculations and separate experiments on test SQUIDs indicate this arrangement will enable us to measure spatial variations of the gauge-invariant phase difference at the atomic scale.

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

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Authors

  • Anita Roychowdhury

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

  • M.A. Gubrud

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

  • Dan Sullivan

    • NASA/Goddard

  • Michael Dreyer

    • University of Maryland
    • Physics Department, University of Maryland and Laboratory for Physical Sciences

  • J.R. Anderson

    • Physics Department, University of Maryland, College Park

  • C.J. Lobb

    • Physics Department, University of Maryland, College Park

  • F.C. Wellstood

    • Physics Department, University of Maryland, College Park