MOLECULAR-DYNAMICS STUDY OF INCOMMENSURATE PHASES IN A 3-DIMENSIONAL CRYSTAL

Two cases of the three-dimensional model-one with incommensurate phases and another with commensurate phases only-have been simulated with use of the molecular-dynamics method. The model crystallite has been subjected to periodic boundary conditions. In the incommensurate regime the phase-transition mechanism consists of nucleation and growth of stripples and antistripples, having the structure described by the domains of the closest reference commensurate phase. The stripple mechanism could not describe the phase transition in the commensurate regime.