INVESTIGADORES
TINTE silvia Noemi
congresos y reuniones científicas
Título:
Dynamical behavior of the phase transition of epitaxial BaTiO3 from atomistic simulations
Autor/es:
S. TINTE, M. SEPLIARSKY
Lugar:
CNEA, Buenos Aires
Reunión:
Workshop; At the Frontiers of Condensed Matter IV; 2008
Resumen:
Using an atomistic shell model we study the temperature dependence of the ferroelectric properties of BaTiO3 under biaxial compressive strain. Molecular dynamics simulations show that 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 low temperature structure, the phase 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.  Histograms of local polarization reveal three different regimes of the dynamical behavior as a function of the temperature. At low temperatures in the ferroelectric phase, the distribution is unimodal centered at a finite value of P_z (out-of-plane  polarization).  In the transition region, the distribution turns bimodal with two unequal peaks at +P_z and -P_z. Finally both peaks equal above T_c in the paraelectric phase.