Reversal transition for polar molecular crystals: critical clusters size analysis and Monte Carlo simulations

摘要

Growing polar molecular crystals (real or model simulations) can undergo a 180 degrees reversal of dipolar building blocks along one particular direction of the polar axis. Here, we analyse the nature of this growth induced reversal transition in terms of (i) a critical cluster size model, (ii) a Markov chain theory, and (iii) Monte Carlo simulations. Present calculations (i) and (iii) let us conclude that reversal is a fundamental property of growing polar seed crystals and that this transition is taking place only for one direction of the polar axis. The final state of the crystal is bi-polar. Application of a Markov chain model (ii) has shown that this description, although valid for stochastic polarity generation in general, fails.