Electrically-controllable superconducting memory effect in UTe2

TL;DR

This paper demonstrates intrinsic superconducting memory in UTe2, where magnetic pulses induce metastable states with different critical currents, highlighting potential for ultralow-power superconducting memory devices.

Contribution

It reveals a novel, intrinsic superconducting memory effect in UTe2 driven by vortex competition, enabling controllable switching without interfaces.

Findings

Magnetic field and current pulses switch UTe2 between metastable states with different critical currents.

Memory states are stable over extended periods, controlled by pulse parameters.

The effect is rooted in vortex dynamics intrinsic to the superconducting order of UTe2.

Abstract

If a computer could be assembled from superconducting components, the energy efficiency would far surpass that of conventional electronics. Historic research efforts towards this goal yielded pivotal breakthroughs in the development and discovery of scanning tunnelling microscopy and high temperature superconductivity. Although recent strides have been taken in advancing superconducting diode and switching technologies, harnessing read/writeable memory functionality in superconducting platforms has remained challenging. Here we show that bulk single crystal specimens of the triplet superconductor candidate uranium ditelluride (UTe$_2$) possess such properties. Upon applying a magnetic field to access an intermediate regime straddling two distinct superconducting phases, we find that direct current pulses can push the material in and out of a metastable state possessing an enhanced critical current $J_c$. This switching is controllable by the strength and duration of the stimuli, with the system `remembering' whether it is in the high or low $J_c$ state for extended periods. We interpret this to be due to competition between two distinct vortex species, which can be perturbatively pushed into a non-equilibrium high-disorder configuration with stronger pinning forces and thus higher $J_c$. Rather than requiring proximate magnetic or semiconducting interfaces, this memory functionality appears to be an intrinsic property of UTe$_2$ rooted in the superconducting order itself. Our findings underscore the rich complexity of quantum vortex matter, and demonstrate the viability of engineering a new class of superconducting memory elements with ultralow-power switching.