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Full-Text Articles in Physical Sciences and Mathematics
Dielectric Response Spectrum Of A Damped One- Dimensional Double-Well Oscillator, John W. Flocken, R. A. Guenther, John R. Hardy, L. L. Boyer
Dielectric Response Spectrum Of A Damped One- Dimensional Double-Well Oscillator, John W. Flocken, R. A. Guenther, John R. Hardy, L. L. Boyer
Physics Faculty Publications
The characteristic features of the dielectric response spectrum associated with the condensation of a "soft" phonon mode during a ferroelectric phase transition can be reproduced by an oscillator moving in a damped linear double-well potential. The behavior of the response function below the transition temperature T, can be simulated by introducing a linear mean-field coupling which destroys the symmetry of the well. Potentials derived from physically realistic parameters are shown to result in dielectric responses which are in order-of-magnitude agreement with experimental values.
Ferroelectricity In Perovskitelike Nacaf3 Predicted Ab Initio, P. J. Edwardson, L. L. Boyer, R. L. Newman, D. H. Fox, John R. Hardy, John R. Flocken, R. A. Guenther, Wai-Ning Mei
Ferroelectricity In Perovskitelike Nacaf3 Predicted Ab Initio, P. J. Edwardson, L. L. Boyer, R. L. Newman, D. H. Fox, John R. Hardy, John R. Flocken, R. A. Guenther, Wai-Ning Mei
Physics Faculty Publications
The ability of zero-stress simulations, using Gordon-Kim pair potentials, to describe the structures and transformations of known fluoride-based perovskites is demonstrated for the case of KCaF3. When K+ is replaced by Na+ a new ferroelectric crystal isomorphous with LiNbO3 is predicted. The equivalent relationships of the ferroelectric lithium niobate structure with the perovskite and antiperovskite structures are examined. A polarization of 21 jµC/cm2 at room temperature and a transition temperature of 550 K are predicted for NaCaF3. Surface effects are examined in simulations of a 1080-ion cluster.