A first-principles study of phase transitions in ultrathin films of BaTiO3
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We determine the effects of film thickness, epitaxial strain and the nature of electrodes on ferroelectric phase transitions in ultrathin films of BaTiO3 using a first-principles effective Hamiltonian in classical molecular dynamics simulations. We present results for polarization and dielectric properties as a function of temperature and epitaxial strain, leading to size-dependent temperature-strain phase diagram for the films sandwiched between ‘perfect’ electrodes. In the presence of non-vanishing depolarization fields when non-ideal electrodes are used, we show that a stable stripe-domain phase is obtained at low temperatures. The electrostatic images in the presence of electrodes and their interaction with local dipoles in the film explain these observed phenomena.
KeywordsFerroelectric phase transition polarization epitaxial strain electrodes
PACS Nos77.90.+k 77.22.Ej 77.80.-e
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- M E Lines and A M Glass, Principles and applications of ferroelectrics and related materials (Oxford University Press, New York, 1977)Google Scholar
- J Paul, T Nishimatsu, Y Kawazoe and U V Waghmare, Phys. Rev. Lett. (in press)Google Scholar
- B P Burton, E J Cockayne and U V Waghmare, Phys. Rev. B72, 064113 (2005)Google Scholar
- O Diéguez, S Tinte, A Antons, C Bungaro, J B Neaton, K M Rabe and D Vanderbilt, Phys. Rev. B69, 212101 (2004)Google Scholar