Emergence of central mode in the paraelectric phase of ferroelectric perovskites
| Autor: | Inna Ponomareva, Jirka Hlinka, Christelle Kadlec, Tetyana Ostapchuk, Petr Kužel, Laurent Bellaiche, Jeevaka Weerasinghe, Sergey Lisenkov |
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| Rok vydání: | 2013 |
| Předmět: |
Materials science
Terahertz radiation FOS: Physical sciences Physics::Optics 02 engineering and technology Soft modes Dielectric 01 natural sciences Condensed Matter::Materials Science Molecular dynamics Phase (matter) Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences General Materials Science 010306 general physics Condensed Matter - Statistical Mechanics Condensed Matter - Materials Science Condensed Matter - Mesoscale and Nanoscale Physics Statistical Mechanics (cond-mat.stat-mech) Condensed matter physics Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology Ferroelectricity Dielectric spectroscopy 0210 nano-technology Solid solution |
| Zdroj: | MRS Communications. 3:41-45 |
| ISSN: | 2159-6867 2159-6859 |
| Popis: | THz-range dielectric spectroscopy and first-principle-based effective-Hamiltonian molecular dynamics simulations were employed to elucidate the dielectric response in the paraelectric phase of (Ba,Sr)TiO3 solid solutions. Analysis of the resulting dielectric spectra suggests the existence of a crossover between two different regimes: a higher-temperature regime governed by the soft mode only versus a lower-temperature regime exhibiting a coupled soft mode/central mode dynamics. Interestingly, a single phenomenological coupling model can be used to adjust the THz dielectric response in the entire range of the paraelectric phase (i.e., even at high temperature). We conclude that the central peak is associated with thermally activated processes, and that it cannot be discerned anymore in the dielectric spectra when the rate of these thermally activated processes exceeds certain characteristic frequency of the system. |
| Databáze: | OpenAIRE |
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