"Dead layer" characteristics based on a correlation of the ferroelectric polarization under relevant boundary conditions in a parallel plate capacitor

Two approaches to modeling the size effect in a ferroelectric parallel plate capacitor are considered: (i) spatial correlation of polarization under the influence of boundary conditions on electrodes of the capacitor and (ii) "dead layer" model. For the description of the spatial correlation, the Landau-Ginzburg-Devonshire equation is used. The characteristic feature of the spatial correlation approach is a correlation parameter α . The dead layer model was first mentioned in 1959 as "a series capacitor model." Phenomenological characteristics of the dead layer are the thickness h d and dielectric constant ε d of the layer. The dead layer model could be useful for practical use as a basis of simulations. Nevertheless one should take into account that the description of the size effect and definitions of the dead layer parameters are based on the correlation of the dynamic ferroelectric polarization in conjunction with the relevant boundary conditions. The estimating of α can be found by processing the experimental data obtained from inelastic neutron scattering. The size effect will be considered without an assumption of any charge transfer and formation of the depletion layers.