Dielectric properties of ferroelectric strained superlattices BaTiO3/SrTiO3

We have developed a phonon-pseudospin coupled model in double-time Green's function theory to investigate dielectric properties of the ferroelectric s trained superlattices BaTiO3/SrTiO3. We have calculated the influence of th e phonon-pseudospin interaction on the dielectric susceptibility. The calcu lation results show that the peak of the dielectric susceptibility shifts u p to higher temperature with increasing the pseudospin interaction, which m eans larger pseudospin interaction corresponds to higher transition tempera ture. As the phonon-pseudospin interaction is strengthened, the intensity a nd position of the susceptibility peak go up and shift to a higher temperat ure, respectively. The peak of the dielectric susceptibility shifts to a hi gher temperature with a rather high intensity when the BaTiO3/SrTiO3 superl attice period increases to a period 5/5, which is consistent with experimen tal results. (C) 2000 Elsevier Science S.A. All rights reserved.