Electrical conductivity enhanced dielectric and ferroelectric properties of interface-coupled ferroelectric superlattices

摘要

We have developed a model to theoretically study the interplay of the effects of interfacial coupling and electrical conductivity on the ferroelectric and dielectric properties of superlattices consisting of alternating ferroelectric and paraelectric layers based on the Landau-Ginzburg theory. The qualitative predictions of the model are compared with recent experimental results for "symmetric" and "asymmetric" superlattices. It is shown that the consideration of time-dependent space-charge-limited conductivity and "interface structure" can satisfactorily account for the enhancement of the overall ferroelectric and dielectric properties of ferroelectric-paraelectrie superlattices.