Disorder and the Ground State in Artificial Spin Ice

Diversity Enabling Equilibration: Disorder and the Ground State in Artificial Spin Ice.
Zoe Budrikis, Paolo Politi, and R. L. Stamps
Phys. Rev. Lett. 107, 217204 (2011)

Left: For an undisordered system, clockwise rotating fields, anticlockwise rotating fields, and a field protocol that alternates sense of rotation every 2 cycles all give the same final energy. Right: The subnetwork of states that can beaccessed from the þx saturated configuration for (a) a perfect system (where the saturated configuration is the large red node) and (b) a typical disordered system.