1996/01/08 by Ph. Ghosez, Ph Ghosez, X. Gonze +3 · 88 citations
Engineering · Materials Science · Physics and Astronomy · #Coulomb #Dielectric #Dielectric materials and actuators #Ferroelectric and Piezoelectric Materials #Ferroelectricity #Instability #Isotropy #Lattice (music) #Phase (matter) #Phonon #Photorefractive and Nonlinear Optics #cond-mat.mtrl-sci #mtrl-th
paper · pdf · doi:10.1209/epl/i1996-00404-8
published in Europhysics Letters (EPL) 33(9), 713-718 (Institute of Physics) · 9 pages, 4 tables, 1 figure
arxiv created 1996/01/08 · openalex publication_date 1996/03/20 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Using first-principles calculations, the phonon frequencies at the Γ-point and the dielectric tensor are determined and analysed for the cubic and rhombohedral phases of BaTiO 3 . The dipole-dipole interaction is then separated à la Cochran from the remaining short-range forces, in order to investigate their respective influence on lattice dynamics. This analysis highlights the delicate balance of forces leading to an unstable phonon in the cubic phase and demonstrates its extreme sensitivity to effective charge changes. Within our decomposition, the stabilization of the unstable mode in the rhombohedral phase or under isotropic pressure has a different origin.