Phonon dispersion and lattice dynamics of KTaO/sub 3/ from 4 to 1220 K

Journal Article · Sat Apr 15 00:00:00 EDT 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.8666· OSTI ID:6406521

Perry, C H; Currat, R; Buhay, H; Migoni, R M; Stirling, W G; Axe, J D

A complete set of transverse and longitudinal phonon branches in each of the three principal directions (<100>, <110>, and <111>) and polarizations have been measured up to 60 meV in the cubic perovskite KTaO/sub 3/. Results were obtained at 296 K and at several other temperatures between 4 and 1220 K. The data have been analyzed in terms of a shell model which includes a fourth-order core-shell interaction at the O/sup 2-/ ion. Within the self-consistent mean-field approximation a very accurate description of the lattice dynamics over the whole temperature range is obtained. It is shown that the nonlinear polarizability of O/sup 2-/ along the Ta-O-Ta chains is primarily responsible for most of the phonon shifts, particularly of the ferroelectric soft mode, and for the strong second-order Raman effect.

• Research Organization: Department of Physics, Northeastern University, Boston, Massachusetts 02115
• OSTI ID: 6406521
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 39:12
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
POTASSIUM COMPOUNDS
PHONONS
AMBIENT TEMPERATURE
AXIAL SYMMETRY
DISPERSION RELATIONS
HIGH TEMPERATURE
MONOCRYSTALS
NEUTRON DIFFRACTION
PEROVSKITE
POLARIZATION
POTASSIUM COMPLEXES
TANTALATES
ALKALI METAL COMPLEXES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COMPLEXES
CRYSTALS
DIFFRACTION
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITES
QUASI PARTICLES
REFRACTORY METAL COMPOUNDS
SCATTERING
SYMMETRY
TANTALUM COMPOUNDS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
360603* - Materials- Properties