An Ambipolar Superconducting Field-Effect Transistor Operating above Liquid Helium Temperature

Area of Science:

• Condensed matter physics
• Materials science
• Quantum technologies

Background:

• Superconducting devices are crucial for advanced quantum information processing, meteorology, and sensing.
• Superconducting field-effect transistors (SC FETs) offer control over superconducting states but have limited variety.
• Achieving higher critical temperatures (T_C) in superconductors often requires higher carrier densities, limiting field-effect control to low temperatures.

Purpose of the Study:

• To report a novel ambipolar superconducting field-effect transistor (SC FET).
• To demonstrate an SC FET operating in a normally OFF mode with an enhanced critical temperature (T_C).
• To explore the potential of this device for fabricating SC circuits and understanding strongly correlated electron systems.

Main Methods:

• Fabrication of a novel ambipolar SC FET device.
• Utilizing organic superconductors with T_C exceeding liquid helium temperature (4.2 K).
• Characterization of the SC FET's operating mode and critical temperature (T_C).

Main Results:

• A novel ambipolar SC FET operating in a normally OFF mode was successfully developed.
• The device exhibits a critical temperature (T_C) of approximately 6 K, exceeding previous SC FETs.
• This represents the second demonstration of an ambipolar SC FET, with a higher operating temperature than magic-angle twisted-bilayer graphene.

Conclusions:

• The developed SC FET demonstrates a higher operating temperature for ambipolar devices.
• The unconventional superconductivity in this device offers potential for advanced SC circuit fabrication.
• This research contributes to the fundamental understanding of phase transitions in strongly correlated electron systems.