Versatile Method of Engineering the Band Alignment and the Electron Wavefunction Hybridization of Hybrid Quantum...

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Hybrid superconductor-semiconductor (S-Sm) devices integrate unique material properties.
• Interface quality dictates coupling strength and wavefunction hybridization.
• Existing methods lack control over S-Sm interface band alignment and tunability.

Purpose of the Study:

• To develop a method for controlled modification of S-Sm interfaces.
• To achieve tunable coupling and hybridization in S-Sm devices.
• To explore fundamental physics in engineered hybrid systems.

Main Methods:

• Interface modification using controlled argon milling.
• Maintaining atomic connection and high interface quality.
• Utilizing Schrödinger-Poisson calculations for analysis.

Main Results:

• Achieved a large induced superconducting gap and ballistic transport.
• Demonstrated control over band bending, coupling strength, and electronic spatial distribution.
• Confirmed coexistence and tunability of crossed Andreev reflection and elastic co-tunneling in the strong coupling regime.
• Successfully applied the method to lead-indium antimonide nanowire (Pb-InSb) devices, creating a hard and huge superconducting gap.

Conclusions:

• The argon milling technique offers precise control over S-Sm interfaces.
• This versatile method is compatible with standard fabrication processes.
• Enables exploration of sophisticated physics in hybrid devices and facilitates the creation of novel quantum devices.