Epitaxial Pb on InAs nanowires for quantum devices

Area of Science:

• Quantum Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Semiconductor-superconductor hybrids are crucial for quantum phenomena like topological superconductivity.
• Existing materials face limitations in high magnetic fields and operating temperatures.
• Developing epitaxially matched materials is key to advancing quantum technologies.

Purpose of the Study:

• To create novel semiconductor-superconductor heterostructures with improved properties.
• To overcome challenges in forming heterostructures with desired quantum characteristics.
• To expand the accessible parameter space for quantum hybrid systems.

Main Methods:

• Utilized expertise in metal-on-semiconductor growth.
• Developed epitaxially matched, single-crystal, atomically flat lead (Pb) films on Indium Arsenide (InAs) nanowires.
• Fabricated InAs/Pb island devices for characterization.

Main Results:

• Achieved highly ordered InAs/Pb heterostructures with no axial grain boundaries.
• Observed a critical temperature of 7 K and a superconducting gap of 1.25 meV.
• Demonstrated robust superconductivity up to 8.5 T, offering twice the parameter space of alternatives.
• Observed magnetic field-driven transitions from Cooper pair to single-electron charging.

Conclusions:

• The developed InAs/Pb heterostructures represent a significant advancement in semiconductor-superconductor materials.
• These materials provide an expanded parameter space for exploring quantum phenomena.
• The findings pave the way for new quantum systems and applications, including topological quantum computation.