REU Student: Charles Tahan, Mentor: Shiwei Zhang

Electromechanical actuators directly transform input electrical energy into mechanical energy. A recent research breakthrough with single crystals of relaxor ferroelectrics (perovskite crystals), which exhibit these piezoelectric properties, has produced samples of these materials that exhibit electromechnical strains exceeding one percent - an order of magnitude higher than conventional polycrystaline piezoelectrics. Because of immense wide-ranging applications, questions as to the fundamental structure and growth mechanisms of these novel materials (with the goal of growing bigger crystals) have drawn much attention. Computer simulations, especially via Kinetic Monte Carlo means, have proved very valuable in deducing the physical processes involved in crystal growth. Up till now, however, KMC has been mostly limited to highly simplified (Ising-like) models, which are not adequate for the materials in question. For example, long-range electrostatic interactions, which have a suggested strong effect on the structure of these types of crystals, are neglected in the current state-of-the-art. Based on previous work, we intend to add these long-range coulomb interactions to the standard KMC model and glean what we can from the results, then go from there, incorporating additonal physical features to study these materials by large-scale simulations.