Strain-Controlled Superconductivity in Few-Layer NbSe₂.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Electronics

Background:

• Low-dimensional materials offer tunable superconductivity for quantum devices.
• Niobium diselenide (NbSe2) exhibits strong spin-orbit coupling, crucial for topological superconductivity.

Purpose of the Study:

• To demonstrate superconductor-insulator transitions in few-layer NbSe2.
• To investigate the role of strain in these transitions.
• To enable scalable tunneling devices for quantum electronics.

Main Methods:

• Epitaxial growth of few-layer NbSe2 on insulating substrates.
• Electrical transport measurements.
• Raman spectroscopy.
• Cross-sectional transmission electron microscopy (TEM).
• X-ray diffraction (XRD).

Main Results:

• Wafer-scale uniformity of epitaxially grown few-layer NbSe2 achieved.
• Superconductor-insulator transitions were successfully demonstrated and characterized.
• Strain was identified as the key driver for the transition.
• Strain-induced energy shifts in Raman modes were observed.

Conclusions:

• Strain engineering provides a method to control superconductivity in NbSe2.
• This work enables the integration of high-quality tunnel barriers within NbSe2.
• Facilitates the development of scalable Josephson junctions and other quantum devices.