We just found a way to make electricity flow in only one direction through a superconductor without using magnets.
April 17, 2026
Original Paper
Strong Correlation Drives Zero-Field Josephson Diode Effect
arXiv · 2604.14045
The Takeaway
Creating a one-way street (a diode) for electricity is the heart of all electronics, but doing it in a superconductor usually requires bulky external magnets. This study shows that the internal interactions between electrons can do the job all on their own. By using strong correlation, the material naturally breaks the rules and forces current to flow better in one direction. It is like a crowd of people naturally deciding to only walk one way through a door without any signs or police. This discovery could finally make superconducting computers practical for everyday use.
From the abstract
The supercurrent diode effect (SDE), characterized by unequal critical currents in opposite directions, has been observed with or without magnetic fields, yet mechanisms enabling zero-field SDE without explicit symmetry breaking remain underexplored. Here we investigate a Josephson junction with strong electron-electron interaction modeled by a Hubbard $U$ term and an odd number of electrons. We find that strong correlations induce spontaneous breaking of time-reversal and mirror symmetries, for