EVOLUTION OF THE DISCOMMENSURATION PATTERNS IN INCOMMENSURATE PHASES

The change of the wave vector modulation in the one-dimensional incommensurate crystal is caused by the topological defects called stripples. The molecular-dynamics simulation of 2d and 3d simple crystalline models has been used to study the structure, nucleation and growth of stripples. Nucleation of a stripple in small simulated crystallites leads to quasi-steps on the kinetic devil's staircase curve. Because of a random character of the nucleation process the kinetic devil's staircase curve becomes continuous in the macroscopic system. This phenomenon leads to the global hysteresis. Nucleated stripples release heat. The simulation of commensurate-incommensurate phase transition has shown that after appearing of the first stripple the remaining stripples are nucleated in a cascade way at the interface between commensurate and incommensurate regions. © 1990, Taylor & Francis Group, LLC. All rights reserved.