The fate of hyperuniform vortex patterns at the surface of type II superconductors

ELÍAS, FEDERICO; RUMI, G.; ARAGÓN SÁNCHEZ, J.; CORTÉS MALDONADO, R.; PUIG, J.; CEJAS BOLECEK, NÉSTOR R.; NIEVA, G.; KONCZYKOWSKI, M.; FASANO, Y.; KOLTON, A.B.

Bariloche

Workshop; Poster en YIELDING PHENOMENA IN DISORDERED SYSTEMS; 2019

Centro Atómico Bariloche - Instituto Balseiro

A many particle system must posses long-range interactions in order to be hyperuniformat thermal equilibrium. Hydrodynamic arguments and numerical simulations show, never-theless, that a three-dimensional elastic-line array with short-ranged repulsive interactions,such as the one induced and directed by a magnetic eld along the z-directionin a superconductor, form at equilibrium a class II hyperuniform two-dimensional point pat-tern in any constant-z cross section, with point density uctuations vanishing isotropicallyas a power law with exponent one at small wavevectors q. This prediction includes both thesolid and liquid vortex phases in the absence of disorder, and also the liquid phase in presenceof weak uncorrelated quenched disorder. We show that the three-dimensional Bragg-glassphase is marginally hyperuniform, while the Bose-glass and the liquid-phase with colum-nar disorder are expected to be non-hyperuniform at equilibrium, with the exception of theMott-Glass phase. Motivated by these theoretical predictions and recent simulations we ex-perimentally study large wavelength vortex density uctuations of magnetically decoratedvortex structures in pristine, electron irradiated and heavy-ion irradiated BSSCO supercon-ducting samples in the mixed state.For most of our samples we nd nearly hyperuniform two-dimensional point patterns at thesuperconductor surface with an eective exponent approximately one. We interpret theseresults in terms of a large-scale memory of the high-temperature line-liquid phase due toglassy dynamics during the eld-cooling protocol. We also discuss the crossovers expectedfrom the dispersivity of the elastic constants at intermediate length-scales, and how nite-size eects in the z-direction should kill the hyperuniformity in the x-y plane for lengths1/q above the superconductor thickness. We argue these predictions may be observable andpropose further experiments to independently test them.