Nanoscale Electrothermal-Switch Superconducting Diode for Electrically Programmable Superconducting Circuits

Superconducting diodes enable dissipationless directional transport, yet achieving electrical tunability and scalability remains a major challenge for circuit-level integration. Here, we demonstrate an electrothermal-switch superconducting diode in which a gate-controlled nanoscale hotspot dynamically breaks inversion symmetry in a superconducting nanowire. This mechanism gives rise to two coexisting non-reciprocal transport regimes, one associated with a non-reciprocal superconducting-to-normal transition and the other with ratchet-like vortex dynamics, both originating from the same electrothermal-switch process. The diode exhibits efficiencies up to 42 and 60% for the two regimes, respectively, and can be electrically switched on, off, or reversed in polarity in situ by applying a small gate current. These capabilities enable programmable superconducting circuits that realize electrically reconfigurable full-wave and half-wave rectification. The lithography-compatible design, high performance, and gate-controlled functionality establish a scalable platform for programmable superconducting electronics and hybrid quantum systems.