A dual tip STM for superconducting phase-difference detection

ORAL

Abstract

We have built a dual tipped Pan-style STM, with each tip capable of independently scanning a sample. We have tested it at room temperature on graphite samples, and calibrated both scanners using atomic steps seen on graphite. We intend to use the STM at ultra-low (mK) temperatures to measure the spatial variation of the gauge-invariant phase difference in superconducting samples at the atomic scale. The two tips will function as the junctions of an asymmetric SQUID, with one tip acting as a reference while the other scans the sample. We will reduce fluctuations in the Josephson phase of the scanning tip by adding capacitance across the junctions and minimizing the geometric inductance.

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Authors

  • Anita Roychowdhury

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

  • M.A. Gubrud

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

  • Dan Sullivan

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

  • Michael Dreyer

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

  • J.R. Anderson

    University of Maryland, JQI, Physics Department, University of Maryland, College Park

  • Christopher Lobb

    University of Maryland, JQI, Physics Department, University of Maryland, College Park, CNAM, University of Maryland, Physics department, University of Maryland

  • F.C. Wellstood

    University of Maryland, JQI, University of Maryland, Physics Department, University of Maryland, College Park