Defects and the central peak near structural phase transitions
- 1 November 1976
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 14 (9), 4030-4044
- https://doi.org/10.1103/physrevb.14.4030
Abstract
The effect of defect or impurities on the static and dynamic response, near a displacive structural phase transition, depends on the symmetry and dynamics of the defect cell. It is shown that a small concentration of defect cells, in which the order parameter relaxes on a slow time scale between different equivalent orientations, may account for the narrow "central peak" as well as for the temperature dependence of the "soft-mode" frequency in the perovskites near structural phase transitions. The case of a frozen defect cell is also discussed. Calculations are performed for the pure and impure systems using mean-field theory, and corrections are discussed using the universality hypotheses and renormalization-group calculations for dynamic critical behavior.Keywords
This publication has 51 references indexed in Scilit:
- Investigation of the central component of SrTiO3 by neutron scattering with eV resolutionPhysics Letters A, 1975
- Preliminary observation of a central peak in the light-scattering spectrum of KPPhysical Review B, 1974
- Critical Dynamics in Srfrom Paramagnetic ResonancePhysical Review Letters, 1974
- Inelastic-Neutron-Scattering Study of Acoustic Phonons inSnPhysical Review B, 1973
- Soft-Phonon Response Function: Inelastic Neutron Scattering from LaA1Physical Review B, 1973
- Critical Neutron Scattering in SrTiand KMnPhysical Review B, 1972
- Dispersion and Damping of Soft Zone-Boundary Phonons in KMnPhysical Review B, 1972
- Critical behaviour of SrTiO3 near the 105°K phase transitionSolid State Communications, 1971
- On the theory of ferroelectricity and anharmonic effects in crystalsPhilosophical Magazine, 1965
- Temperature Dependence of the Dielectric Constant of Paraelectric MaterialsPhysical Review B, 1963