Onset of Ferrielectricity and the Hidden Nature of Nanoscale Polarization...

Using calculations from first principles and the concept of layer polarization, we have elucidated the
nanoscale organization and local polarization in ferroelectric thin films between metallic contacts. The profile of the local polarization for different film thicknesses unveils a peculiar spatial pattern of atomic
layers with uncompensated dipoles in what was originally thought to be a ferroelectric domain. This
effectively ferrielectric behavior is induced by the dominant roles of the interfaces at such reduced
dimensionality and can be interpreted using a simple classical model where the latter are explicitly taken into account.