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Dissipationless Counterflow Currents above T_{c} in Bilayer Superconductors
Guido Homann1, Marios H Michael2, Jayson G Cosme3
1Zentrum für Optische Quantentechnologien and Institut für Quantenphysik, Universität Hamburg, 22761 Hamburg, Germany.
Physical Review Letters
|March 15, 2024
Summary
Dissipationless counterflow currents exist in bilayer superconductors above the critical temperature (Tc). Thermal fluctuations cause vortex proliferation, leading to dissipation of in-plane currents but not counterflow currents.
Area of Science:
- Condensed Matter Physics
- Superconductivity Theory
Background:
- Superconducting phase transitions are often influenced by phase fluctuations.
- Understanding the behavior of superconductors above the critical temperature (Tc) is crucial for technological applications.
Purpose of the Study:
- To investigate the existence of dissipationless currents in bilayer superconductors above Tc.
- To explore the role of thermal fluctuations and vortex excitations in the superconducting state.
Main Methods:
- Utilized a semiclassical U(1) lattice gauge theory.
- Analyzed the impact of thermal fluctuations on superconducting states and vortex proliferation.
Main Results:
- Identified a transition from a superconducting to a resistive state above Tc due to thermal fluctuations and unbound vortices.
- Demonstrated that while homogeneous in-plane currents dissipate, counterflow currents within bilayers remain dissipationless.
Conclusions:
- Dissipationless counterflow currents above Tc are enabled by inhibited vortex motion due to local coherence within bilayers.
- This phenomenon offers a potential explanation for the pseudogap phase observed in bilayer cuprates.
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