IMF2017

This presentation will discuss the recent observations and predictions of new thermodynamically stable mesoscale polar states that might emerge from ferroelectric heterostructures at the nanoscale. In presentation, we focus on the determination of thermodynamic conditions and geometric length scales that are critical for the formation of ordered polar vortex lattice in ferroelectric superlattices of PbTiO₃/SrTiO₃ using phase-field simulations and analytical theory. We show that the stability of these vortex lattices involves an intimate competition between long-range electrostatic, long-range elastic, and short-range polarization gradient-related interactions leading to both an upper- and a lower- bound to the length scale at which these states can be observed. We found that the critical length is related to the intrinsic domain wall width, which could serve as a simple intuitive design rule for the discovery of novel ultrafine topological structures in ferroic systems.