Nonmonotonic Temperature-Dependent Dissipation at Nonequilibrium in Atomically Thin Clean-Limit Superconductors.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Superconductor resistance is typically linked to vortex motion.
• Lowering temperature usually suppresses vortex motion and reduces resistance.
• Existing models do not explain non-monotonic resistance behavior.

Purpose of the Study:

• Investigate the anomalous resistance behavior in atomically thin superconductors.
• Explore the role of thermal fluctuations in vortex dynamics.
• Propose a new model for vortex mobility and dissipation.

Main Methods:

• Experimental measurements of resistance in clean-limit atomically thin 2H-NbSe2.
• Device fabrication focusing on monolayer structures.
• Analysis of temperature-dependent resistance below the superconducting transition.

Main Results:

• Observed non-monotonic resistance in 2H-NbSe2, decreasing to a minimum then increasing with further cooling.
• The effect was most pronounced in monolayer devices.
• The observed behavior deviates from established theories of vortex motion.

Conclusions:

• A novel two-fluid vortex model is proposed, involving thermal fluctuations of pinned vortices influencing free vortex mobility.
• Findings challenge conventional understanding of vortex mobility and dissipation in superconductors.
• The study opens new avenues for exploring fundamental physics in thin-film superconductors.