Sotf mode in cubic PbTiO3 by hyper-Raman scattering Auteur(s): Hlinka J., Hehlen B., Kania A., Gregora I. (Article) Publié: -Physical Review B Condensed Matter And Materials Physics (1998-2015), vol. p.064101 (2013) Texte intégral en Openaccess : Ref HAL: hal-00797857_v1 DOI: 10.1103/PhysRevB.87.064101 WoS: 000314681700003 Exporter : BibTex | endNote 10 Citations Résumé: Hyper-Raman scattering experiments allowed collecting the spectra of the lowest F1u-symmetry mode of PbTiO3 crystal in the paraelectric phase up to ≈930 K as well as down to about 1 K above the phase transition. It is realized that this mode is fully responsible for the Curie-Weiss behavior of its dielectric permittivity above Tc. Near the phase transition, this phonon frequency softens down to 17 cm-1 and its spectrum can be well modeled as a response of a single damped harmonic oscillator. It is concluded that PbTiO3 constitutes a clean example of a soft-mode-driven ferroelectric system. |