Electrically controllable superconducting memory effect in UTe2

Abstract

Abstract Multiphase superconductors—materials that host two or more distinct superconductive phases—are exceptionally rare. Examples include heavy-fermion CeRh 2 As 2 alongside some uranium compounds such as UPt 3 and URhGe (refs. 1,2,3 ). In the multiphase p -wave superfluid 3 He, complex vortex dynamics can occur at the phase boundary between the A and B phases 4,5 . Here we study the p -wave superconductor candidate UTe 2 (refs. 6–8 ). On applying a magnetic field to access an intermediate regime straddling two distinct superconducting phases 9,10 , we find that direct current pulses can push the material in and out of a metastable state that has an enhanced critical current density 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 phenomenology to be due to the quenching of a disordered out-of-equilibrium glassy vortex state under perturbation, which has stronger pinning forces and thus higher J c . The equilibrium vortex lattice is reattained by annealing the system with a gradual current ramp, returning it to the original state. Rather than requiring proximate magnetic or semiconducting interfaces 11–14 , this memory functionality seems to be an intrinsic property of UTe 2 rooted in the superconducting order itself. Our findings underscore the rich complexity of multiphase quantum vortex matter.