A model for a 2-dimensional crystal that was subjected to a slowly varying random potential was analyzed. Evidence was found for the existence of a zero-temperature phase transition via the appearance of isolated dislocations above a critical degree of disorder. This result contrasted with earlier analyses of the model, which had predicted that the crystal was always unstable with respect to dislocation formation. The result was generalized to finite temperatures, and a phase boundary was derived. Molecular dynamics simulations of a model electron crystal revealed strong evidence for the occurrence of this phase transition at low temperatures.

Disorder-Induced Phase Transitions in Two-Dimensional Crystals. M.C.Cha, H.A.Fertig: Physical Review Letters, 1995, 74[24], 4867-70