High-Performance Gate-Controlled Superconducting Switches: Large Output Voltage and Reproducibility.

Area of Science:

• Condensed Matter Physics
• Superconducting Electronics
• Quantum Computing Components

Background:

• Superconducting logic circuits offer potential for high-performance computing.
• Gate-controlled supercurrent (GCS) is a key phenomenon for developing superconducting logic.
• Previous GCS research faced challenges in reproducibility and performance optimization.

Purpose of the Study:

• To investigate the reproducibility and performance of gated niobium (Nb) devices exhibiting GCS.
• To explore the relationship between GCS, constriction width, and leakage current.
• To enhance voltage output for improved device interconnectivity in superconducting logic.

Main Methods:

• Fabrication and characterization of multiple gated Nb devices.
• Systematic investigation of GCS behavior with varying gate voltage (V_G).
• Statistical analysis of device performance, including GCS, leakage current (I_leak), and voltage output.

Main Results:

• Demonstrated highly reproducible GCS in gated Nb devices.
• Found GCS is independent of constriction width, contrary to prior findings.
• Confirmed a strong correlation between GCS and V_G-induced leakage current (I_leak).
• Achieved voltage output exceeding previous reports by over an order of magnitude.
• Showcased I_leak as a tool to modulate operational V_G on SiO2 substrates.

Conclusions:

• The study significantly advances the optimization of GCS device reproducibility and performance.
• Results pave the way for the development of practical superconducting logic circuits.
• Identified key parameters (I_leak) for controlling and optimizing GCS device operation.