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Scanning-probe Single-electron Capacitance Spectroscopy
Published on: July 30, 2013
Fluctuation dominated Josephson tunneling with a scanning tunneling microscope
O Naaman1, W Teizer, R C Dynes
1Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0319, USA.
Physical Review Letters
|September 5, 2001
Summary
We observed Josephson tunneling in superconducting vacuum junctions. Thermal fluctuations dominate phase dynamics, causing Josephson current peaks at low voltages, which are suppressed by microwave fields.
Area of Science:
- Solid State Physics
- Quantum Phenomena
Background:
- Superconducting quantum effects are crucial for advanced electronics.
- Vacuum tunnel junctions offer unique platforms for studying quantum phenomena.
Purpose of the Study:
- To investigate Josephson tunneling in superconducting vacuum tunnel junctions.
- To analyze the influence of thermal fluctuations and microwave fields on superconducting phase dynamics.
Main Methods:
- Fabrication of vacuum tunnel junctions using a superconducting scanning tunneling microscope tip and a lead (Pb) film.
- Measurement of Josephson tunneling currents across junctions with resistances in the 50-300 k Omega range.
- Application of microwave fields (15.0 GHz) to probe the response of the Josephson current.
Main Results:
- Demonstration of Josephson tunneling in superconducting vacuum tunnel junctions.
- Observation that thermal fluctuations dominate superconducting phase dynamics.
- Identification of a Josephson current peak at small finite voltages.
- Quantification of the decrease in Josephson current magnitude and shift to higher voltages with increasing microwave power.
Conclusions:
- Superconducting vacuum tunnel junctions are viable for studying Josephson tunneling.
- Thermal fluctuations play a significant role in the observed superconducting phase dynamics.
- The behavior of Josephson current under microwave irradiation aligns with theoretical predictions.
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