Ising-like transition and phason unlocking in icosahedral quasicrystals

Using Monte Carlo computer simulations, we find strong evidence for a novel, finite-temperature, Ising-like transition in the alignment of unit cells in icosahedral quasicrystals. The Ising-like transition may be related to the transition in phason behavior from a locked (Penrose-tiling-like) phase at low temperatures to an unlocked (random-tiling-like) phase at high temperatures.