Predicting polarization and nonlinear dielectric response of arbitrary   perovskite superlattice sequences
  We carry out first-principles calculations of the nonlinear dielectric response of short-period ferroelectric superlattices. We compute and store not only the total polarization, but also the Wannier-based polarizations of individual atomic layers, as a function of electric displacement field, and use this information to construct a model capable of predicting the nonlinear dielectric response of an arbitrary superlattice sequence. We demonstrate the successful application of our approach to superlattices composed of SrTiO$_3$, CaTiO$_3$, and BaTiO$_3$ layers. 
Xifan Wu, Massimiliano Stengel, Karin M. Rabe, and David Vanderbilt