Fluctuation dominated Josephson tunneling with a scanning tunneling microscope.
We demonstrate Josephson tunneling in vacuum tunnel junctions formed between a superconducting scanning tunneling microscope tip and a Pb film, for junction resistances in the range 50-300 k Omega. We show that the superconducting phase dynamics is dominated by thermal fluctuations, and that the Josephson current appears as a peak centered at small finite voltage. In the presence of microwave fields ( f = 15.0 GHz) the peak decreases in magnitude and shifts to higher voltages with increasing rf power, in agreement with theory.
Naaman
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Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0319, USA.
Teizer
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Dynes
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