Coupled displacive and order-disorder dynamics in LiNbO_(3) by molecular-dynamics simulation

摘要

We demonstrate that molecular-dynamics simulations can reproduce the ferroelectric behavior of LiNbO_(3) and the ferroelectric-paraelectric phase transition. We find that this phase transition is a two-stage process involving a displacive transition in the Nb-O cages at a temperature below the Curie temperature and an order-disorder transition in the Li-O planes at the Curie temperature itself.