K. Parlinski, PRINCIPLES OF COMPUTER-SIMULATION OF PHASE-TRANSITIONS AND DOMAIN PATTERN IN FERROIC SYSTEMS, Journal of the Korean Physical Society, 32, 1998, pp. 711-714
The procedure to study the structural phase transition and the related
domain pattern requires formulation of a model consistent with symmet
ry of the high-and low-symmetry phases of the crystal. The harmonic mo
des, including the soft mode, can be found from ab initio calculations
, by the direct method, which uses the Hellmann-Feynman forces. Exampl
es of ferroelastic systems which have been simulated, are referenced.