Excess of topological defects induced by confinement in vortex nanocrystals

BOLECEK, N. R. CEJAS; DOLZ, M. I.; PASTORIZA, H.; KONCZYKOWSKI, M.; VAN DER BEEK, C. J.; KOLTON, A. B.; FASANO, Y.

Physical Review B

APS

Año: 2017 vol. 96

2469-9950

We directly image individual vortex positions in nanocrystals in order to unveil the structural property thatcontributes to the depletion of the entropy jump entailed at the first-order transition. On reducing the nanocrystalsize, the density of topological defects increases near the edges over a characteristic length. Within this ?healing-length? distance from the sample edge, vortex rows tend to bend, while towards the center of the sample, thepositional order of the vortex structure is what is expected for the Bragg-glass phase. This suggests that thehealing length may be a key quantity to model confinement effects in the first-order transition of extremelylayered vortex nanocrystals.