Dynamical behavior of the phase transition of strained from atomistic simulations

✍ Scribed by Marcelo Sepliarsky; Silvia Tinte

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 226 KB
• Volume: 404
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2009.06.079

✦ Synopsis

Using an atomistic shell model we study the temperature dependence of the ferroelectric properties of BaTiO 3 under biaxial compressive strain applicable to growth on perovskites substrate. Molecular dynamics simulations show a ''r ! c ! p'' sequence of phase transitions when temperature is increased, and the absence of an ''ac phase''. The first-order paraelectric-to-ferroelectric phase transition presents in bulk changes to a second-order one as a consequence of the in-plane constraint imposed by the mechanical boundary conditions. From the tetragonal ferroelectric c phase, the transition takes place in a finite range of temperature where the lattice parameter normal to the plane keeps approximately constant until T c is reached. Analysis of the local polarization behavior reveals an order-disorder dynamics as the dominant mechanism of the transition.