Surface and substrate effects on the ferroelectric properties of PbTiO3 ultrathin films

M.SEPLIARSKY; M.G.STACHIOTTI; R.L.MIGONI

FERROELECTRICS

Taylor & Francis

Lugar: Philadelphia; Año: 2006 vol. 335 p. 3 - 12

0015-0193

The effects of the antiferrodistortive surface reconstruction and the interface with a SrTiO3 substrate on the ferroelectric properties of PbTiO3 ultrathin films are investigated using an interatomic potential approach with parameters determined from first-principles results. First we show that a shell model developed for the bulk describes properly the surface properties of PbTiO3, in particular the antiferrodistortive surface reconstruction recently observed from x-ray scattering. We investigate also the effects of the surface reconstruction on the polarization behavior of ultrathin films under open-circuit electrical boundary conditions, showing that the surface layer participates in the ferroelectricity. Finally, film-substrate interface effects on the ferroelectric properties are investigated simulating PbTiO3 ultrathin films on a SrTiO3   substrate.