Molecular Dynamics Simulations of Chemically Disordered Ferroelectric (Ba,Sr)TiO$_3$ with a Semi-Empirical Effective Hamiltonian
| Autor: | Nishimatsu, Takeshi, Gruenebohm, Anna, Waghmare, Umesh V., Kubo, Momoji |
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| Rok vydání: | 2016 |
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| Zdroj: | J. Phys. Soc. Jpn. 85, 114714 (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.7566/JPSJ.85.114714 |
| Popis: | We present a semi-empirical effective Hamiltonian to capture effects of disorder associated with Ba and Sr cations occupying $A$ sites in (Ba$_{x}$Sr$_{1-x}$)TiO$_3$ on its ferroelectric phase transition. Averaging between the parameters of first-principles effective Hamiltonians of end members BaTiO$_3$ and SrTiO$_3$, we include a term with an empirical parameter to capture the local polarization and strains arising from the difference between ionic radii of Ba and Sr. Using mixed-space molecular dynamics of the effective Hamiltonian, we determine $T$-dependent ferroelectric phase transitions in (Ba$_{x}$Sr$_{1-x}$)TiO$_3$ which are in good agreement with experiment. Our scheme of determination of semi-empirical parameters in effective Hamiltonian should be applicable to other perovskite-type ferroelectric solid solutions. Comment: 7 pages, 6 figures, submitted to JPSJ |
| Databáze: | arXiv |
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