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Superconductivity from a melted insulator in Josephson junction arrays
S Mukhopadhyay1, J Senior1, J Saez-Mollejo1
1IST Austria, Klosterneuburg, Austria.
Nature Physics
|November 16, 2023
Summary
Josephson arrays with strong interactions unexpectedly show decreased resistance at low temperatures, behaving like superconductors. This apparent superconductivity arises from thermal fluctuations melting a zero-temperature insulator.
Area of Science:
- Condensed matter physics
- Quantum phenomena
Background:
- Josephson junction arrays are systems where superconductivity competes with repulsive Coulomb interactions.
- Theoretical models predict diverging low-temperature resistance when interactions exceed a critical level.
Purpose of the Study:
- To investigate the transport and microwave response of Josephson arrays with interactions exceeding the critical level.
- To understand the low-temperature behavior of these arrays contrary to theoretical expectations.
Main Methods:
- Experimental study of transport properties.
- Microwave response measurements.
- Application of magnetic fields.
Main Results:
- Observed dramatic drop in array resistance with decreasing temperature, resembling superconductivity.
- Resistance saturated at low temperatures.
- Observed a transition to a highly resistive regime upon applying a magnetic field.
Conclusions:
- The observed behavior is explained by thermal fluctuations affecting the insulating phase.
- Apparent superconductivity in these arrays is attributed to the melting of a zero-temperature insulator.
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