A first-principles study of phase transitions in ultrathin films of BaTiO3

Pramana

J Paul¹  T Nishimatsu2²  U V Waghmare1¹  Y Kawazoe² 

[1] Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India$$;Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan$$

关键词: Ferroelectric phase transition;    polarization;    epitaxial strain;    electrodes.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

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.

【 授权许可】

Unknown