Ferroelectric phase transitions and dynamical behavior in KNbO3/ KTaO3 superlattices by molecular-dynamics simulation

M. SEPLIARSKY; S. PHILLPOT; D. WOLF; M. G. STACHIOTTI; R. L. MIGONI

JOURNAL OF APPLIED PHYSICS

AMER INST PHYSICS

Lugar: New York; Año: 2002 vol. 91 p. 3165 - 3171

0021-8979

The phase transitions and dynamical behavior of superlattices consisting of equal-thickness layers ofa perovskite ferroelectric ͑KNbO 3 ͒ and a perovskite paraelectric ͑KTaO 3 ͒ are explored usingmolecular-dynamics simulation. We find that the response in the plane and in the modulationdirection are essentially decoupled. The Curie temperature for the transition from a polarized tounpolarized state in the modulation direction decreases approximately linearly with modulationlength, ⌳, for ⌳Ͼ12; for smaller modulation lengths, it is essentially constant. The Curietemperature in the plane appears to be only weakly modulation-length dependent. We relate ourresults to experimental findings on the same system.