Uncertainty analysis of continuum phase field modeling in 180° degree domain wall structures

Abstract

The evolution and formation of domain structures in ferroelectric materials is modeled using a continuum phase field approach and compared with density functional theory (DFT) using Bayesian uncertainty analysis. These simulations are carried out on the ferroelectric, lead titanate. Self-consistency between DFT and the continuum approach is advantageous when computing polydomain structures and domain wall dynamics. There is uncertainty in the phenomenological parameters related to the Landau energy, electrostriction, and twinned domain wall energy in single and polydomain ferroelectric crystals. To quantify the model parameter uncertainty associated with the phase field model, Bayesian statistics were used. Specifically, we will focus on estimating the value of the exchange parameters associated with polarization gradients. The phase field model predictions for the 180° domain wall energy are calibrated based upon DFT calculations. Model predictions of domain wall size are found to be on the same order as DFT calculations.