Hybrid high-temperature-superconductor-semiconductor tunnel diode

We report the demonstration of hybrid high-T_c-superconductor-semiconductor tunnel junctions, enabling new interdisciplinary directions in condensed matter research. The devices are fabricated by our newly developed mechanical-bonding technique, resulting in high-T_c-superconductor-semiconductor tunnel diodes. Tunneling-spectra characterization of the hybrid junctions of Bi₂Sr₂CaCu₂O_8+δ combined with bulk GaAs, or a GaAs/AlGaAs quantum well, exhibits excess voltage and nonlinearity, similarly to spectra obtained in scanning-tunneling microscopy, and is in good agreement with theoretical predictions for a d-wave-superconductor-normal-material junction. Additional junctions are demonstrated using Bi₂Sr₂CaCu₂O_8+δ combined with graphite or Bi₂Te₃. Our results pave the way for new methods in unconventional superconductivity studies, novel materials, and quantum technology applications.