Printable two-dimensional superconducting monolayers.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Non-centrosymmetric two-dimensional superconductors (2DSCs) show unique Ising pair superconductivity and high critical fields.
• Challenges include structural disorder and oxidation, hindering device fabrication and electronic coherence.

Purpose of the Study:

• To develop a general, scalable, and mild synthesis for highly crystalline 2DSC monolayers.
• To demonstrate the potential of these monolayers in fabricating stable van der Waals heterostructures (vdWHs) and superconducting devices.

Main Methods:

• Mild electrochemical exfoliation using flexible organic ammonium cations and neutral solvent co-intercalants.
• Synthesis of large-sized (up to 300 µm) single-crystal NbSe2 monolayers with high yield (>75%).
• Fabrication of twisted NbSe2 vdWHs and superconducting inks.

Main Results:

• Achieved high yield and large size of crystalline 2DSC monolayers (NbSe2).
• Demonstrated stable twisted NbSe2 vdWHs with good interfacial properties.
• Observed magnetic field-modulated critical current in vdWHs, linked to moiré cell flux quantization.
• Formulated 2DSC inks for wafer-scale wire arrays and 3D composites.

Conclusions:

• The electrochemical exfoliation method provides a scalable route to high-quality 2DSC monolayers.
• The synthesized materials are suitable for fabricating robust vdWHs and advanced superconducting devices.
• This work opens avenues for novel electronic and composite applications of 2D superconductors.