1National Laboratory of Solid State Microstructures and Center for Materials Analysis, Nanjing University, Nanjing 210093
2Institute of Physics, Chinese Academy of Sciences, Beijing 100080
Dielectric Characteristics and Layer Periodic Effects of Ferroelectric Superlattice BaTiO3/SrTiO3
1National Laboratory of Solid State Microstructures and Center for Materials Analysis, Nanjing University, Nanjing 210093
2Institute of Physics, Chinese Academy of Sciences, Beijing 100080
Abstract： A pseudospin-phonon coupled model in double-time Green's function theory has been developed to investigate dielectric susceptibility of the ferroelectric-dielectric superlattice BaTiO3/SrTiO3(BTO/STO). As the pseudospin-pseudospin interaction and the pseudospin-phonon interactions increase, the dielectric susceptibility changes from narrow shape into the strong-broad shape with the peak shift to higher temperature region. With increasing pseudospin-phonon interaction in the BTO layer and at small pseudospin-pseudospin interaction in BTO layer, the dielectric susceptibility was sensitively adjusted around the transition temperature of strontium titanate, and at large pseudospin-pseudospin interaction in the BTO layer, the dielectric susceptibility was increased in high temperature region covering the tetragonal-cubic transition temperature of barium titanate. A critical period of 10/10 in the BTO/STO superlattice has been obtained, which is in good agreement with experimental data of 40Å, for ten unit cells.
2001, Vol. 18 
