Attojoule Superconducting Thermal Logic and Memories

Due to stringent thermal budgets in cryogenic technologies such as superconducting quantum computers and sensors, electronic building blocks that simultaneously offer low energy consumption, fast switching, low error rates, a small footprint, and simple fabrication are pivotal for large-scale devices. Here, we demonstrate a superconducting switch with attojoule switching energy, high speed (pico-second rise/fall times), and high integration density (on the order of 10^-2 μm² per switch). It consists of a superconducting nanochannel and a metal heater separated by an insulating silica layer. We experimentally demonstrate digital gate operations utilizing these nanostructures, such as NOT, NAND, NOR, AND, and OR gates, with a few femtojoules of energy consumption and ultralow bit error rates <10^-8. In addition, we build energy-efficient volatile memory elements with nanosecond operation speeds and a retention time over 10⁵ s. These superconducting switches open new possibilities for increasing the size and complexity of modern cryogenic technologies.