Freezing and melting of vortex ice

TL;DR

This paper demonstrates the creation of artificial vortex ice in superconductors, which can be toggled between frozen and melted states via temperature, with dynamics unaffected by annealing, highlighting thermal fluctuation effects.

Contribution

It introduces a novel vortex ice system with temperature-controlled frustration and spontaneous ordering, driven by thermal fluctuations and vortex interactions.

Findings

Vortex ice can be switched on/off by temperature variations.

Frozen vortex ice shows insensitivity to annealing.

Thermal fluctuations and vortex interactions drive spontaneous ordering.

Abstract

We report on the realization of artificial ice using superconducting vortices in geometrically frustrated pinning arrays. This vortex ice shows two unique properties among artificial ice systems. The first comes from the possibility to switch the array geometric frustration on/off through temperature variations, which allows "freezing" and "melting" the vortex ice. The second is that the depinning and dynamics of the frozen vortex ice are insensitive to annealing, which implies that the ordered ground state is spontaneously approached. The major role of thermal fluctuations and the strong vortex-vortex interactions are at the origin of this unusual behavior.