Calculations on switching characteristics of ferroelectric–paraelectric superlattices

We study the switching characteristics of a superlattice consisting of a periodic ferroelectric and paraelectric layer with interlayer coupling using the Landau–Khalatnikov equation. The inhomogeneity of polarization at the ferroelectric or paraelectric surface is described by the extrapolation length δ. The effects of various parameters such as the viscosity coefficient, layer thickness, interlayer coupling and temperature on the switching characteristics are investigated. Our study shows that the hysteresis loop and switching current versus applied field depend strongly on those parameters. Interlayer coupling increases the ferroelectricity of the superlattice, leading to a strong enhancement in polarization and coercive field.