DC Self-Field Critical Current in Superconductor Dirac-Cone Material/Superconductor Junctions

Area of Science:

• Condensed Matter Physics
• Superconductivity
• Materials Science

Background:

• Superconductor/Dirac-cone material/superconductor (S/DCM/S) junctions exhibit anomalous enhancement of self-field critical currents (I(sf,T)) at low temperatures.
• Existing theories often attribute this enhancement to low-energy Andreev bound states in Dirac-cone materials.

Purpose of the Study:

• To analyze and compare the effectiveness of the modified Ambegaokar-Baratoff and ballistic Titov-Beenakker models in describing I(sf,T) in S/DCM/S junctions.
• To identify the most suitable theoretical model for explaining experimental data in these systems.

Main Methods:

• Comparative analysis of two theoretical models: modified Ambegaokar-Baratoff and ballistic Titov-Beenakker.
• Application of these models to analyze experimental data of I(sf,T) in S/DCM/S junctions.

Main Results:

• The ballistic Titov-Beenakker model is found to be inadequate for analyzing experimental data in S/DCM/S junctions.
• The modified Ambegaokar-Baratoff model, typically used for superconductor/insulator/superconductor junctions, provides a good description of the experimental data.

Conclusions:

• The traditional ballistic model is insufficient for understanding self-field critical currents in S/DCM/S systems.
• A new theoretical model is required to accurately describe I(sf,T) in superconductor/Dirac-cone material/superconductor junctions.