Entropic commensurate-incommensurate transition
  The equilibrium properties of a minimal tiling model are investigated. The model has extensive ground state entropy, with each ground state having a quasiperiodic sequence of rows. It is found that the transition from the quasiperiodic ground state to the high temperature disordered phase proceeds through a sequence of periodic arrangements of rows, in analogy with the Frenkel-Kontorova model, but with temperature playing the role of the strength of the substrate potential. 
Nikolai Nikola, Daniel Hexner, Dov Levine
cond-mat.stat-mech