Dynamic displacement disorder of cubic BaTiO.sub.3./sub.

0490147 - FZÚ 2019 RIV US eng J - Journal Article
Pasciak, Marek - Welberry, T.R. - Kulda, J. - Leoni, S. - Hlinka, Jiří
Dynamic displacement disorder of cubic BaTiO₃.
Physical Review Letters. Roč. 120, č. 16 (2018), s. 1-6, č. článku 167601. ISSN 0031-9007. E-ISSN 1079-7114
R&D Projects: GA ČR GA15-04121S
Institutional support: RVO:68378271
Keywords : anharmonic lattice dynamics * ferroelectricity * phase transitions * phonons * x-ray diffuse scattering * molecular dynamics simulations
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 9.227, year: 2018

The three-dimensional distribution of the x-ray diffuse scattering intensity of BaTiO3 has been recorded in a synchrotron experiment and simultaneously computed using molecular dynamics simulations of a shell model. Together, these have allowed the details of the disorder in paraelectric BaTiO3 to be clarified. The narrow sheets of diffuse scattering, related to the famous anisotropic longitudinal correlations of Ti ions, are shown to be caused by the overdamped anharmonic soft phonon branch. This finding demonstrates that the occurrence of narrow sheets of diffuse scattering agrees with a displacive picture of the cubic phase of this textbook ferroelectric material. The presented methodology allows one to go beyond the harmonic approximation in the analysis of phonons and phonon-related scattering.
Permanent Link: http://hdl.handle.net/11104/0284440