Crystalline Germanium Josephson Junctions

Demonstrates fully epitaxial Ga:Ge/Si/Ga:Ge Josephson junctions grown in situ by molecular beam epitaxy. The 0.5 nm crystalline Si weak link retained atomically continuous interfaces and strong Josephson coupling. The work positions the material stack as a compact, CMOS-compatible mergemon pathway but does not demonstrate a qubit.

Key Results

• Fully crystalline Ga:Ge/Si/Ga:Ge Josephson junctions
• 0.5 nm Si weak-link layer between 10 nm Ga:Ge electrodes
• Strong Josephson coupling in the ultrashort regime
• Materials precursor only; no qubit coherence measurement

Links

• arXiv: 2608.08500

Zoo Links

• mergemon
• all-semiconductor-superconducting-qubit