Attojoule superconducting thermal logic and memories

TL;DR

This paper introduces a superconducting switch with attojoule energy consumption, pico-second switching speeds, and high integration density, enabling advanced cryogenic digital logic and memory with ultralow error rates.

Contribution

The work demonstrates a novel superconducting switch with unprecedented low energy, high speed, and high integration density, along with practical digital gates and memory elements.

Findings

Switch energy consumption in the attojoule range.

Digital gates with femtojoule energy use and ultralow error rates.

Memory elements with nanosecond speed and long retention times.

Abstract

Due to stringent thermal budgets in cryogenic technologies such as superconducting quantum computers and sensors, minimizing the energy dissipation and power consumption of cryogenic electronic components is pivotal for large-scale devices. However, electronic building blocks that simultaneously offer low energy consumption, fast switching, low error rates, a small footprint and simple fabrication remain elusive. In this work, we demonstrate a superconducting switch with attojoule switching energy, high speed (pico-second rise/fall times), and high integration density (on the order of $10^{-2}$ $\mathrm{\mu m^2}$ per switch). The switch consists of a superconducting channel and a metal heater separated by an insulating silica layer, prepared using lift-off techniques. We experimentally demonstrate digital gate operations utilizing this technology, such as NOT, NAND, NOR, AND, and OR gates, with a few femtojoule energy consumption and ultralow bit error rates < $10^{-8}$. In addition, we build volatile memory elements with few femtojoule energy consumption per operation, a nanosecond operation speed, and a retention time over $10^5$ s. These superconducting switches open new possibilities for increasing the size and complexity of modern cryogenic technologies.