Competition between topological order and long range order in Santa Fe spin ice

Artificial spin ices are two-dimensional arrays of interacting single-domain ferromagnetic nano-islands [1,2]. Santa Fe Ice is a newly proposed and recently realized artificial spin ice lattice whose vertex-frustrated [3,4] spin ensemble can be described by strings of topologically protected excitations. We have investigated numerically Santa Fe Ice in and out of equilibrium. Depending on structural parameters, its ground state can either be a disordered topological phase [5,6] or an ordered, anti-ferromagnetic state. In the latter case, however, the topological phase is still present and can trap the system, delaying or preventing the relaxation to the ordered state either after quenches or even after a slow annealing when in the neighborhood of the structural transition.
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