First-Principles Investigations of Pb_(0.5)Ba_(0.5)TiO_3 Alloys Based on Structure Predictions  

作　　者：吴宏博 段益峰 赵昌明 刘坤 秦丽霞 

机构地区：[1]Department of Physics,China University of Mining and Technology

出　　处：《Chinese Physics Letters》2016年第4期134-138,共5页中国物理快报（英文版）

基　　金：Supported by the Fundamental Research Funds for the Central Universities under Grant No 2013QNA38

摘　　要：Crystal structure predictions of Pb0.5Ba0.5 Ti03 alloys under different pressures are performed based on the parti- cle swarming optimization algorithm. The predicted stable ground-state and high-pressure phases are tetragonal ferroelectric （I4mm） and cubic para-electric （Fm3m）, respectively, whose structural details have not been re- ported. The pressure-induced colossal enhancements in piezoelectric response are associated with the mechanical and dynamical instabilities instead of polarization rotation. The band gap of the tetragonM phase is indirect and that of the cubic phase is always direct. As pressure increases, the alloy displays the similar band-gap behaviors to PbTiO3, while different from BaTiO5, which is attributed to the different orbital contributions to the valence bands. Our calculated results are in good agreement with the available data.Crystal structure predictions of Pb0.5Ba0.5 Ti03 alloys under different pressures are performed based on the parti- cle swarming optimization algorithm. The predicted stable ground-state and high-pressure phases are tetragonal ferroelectric （I4mm） and cubic para-electric （Fm3m）, respectively, whose structural details have not been re- ported. The pressure-induced colossal enhancements in piezoelectric response are associated with the mechanical and dynamical instabilities instead of polarization rotation. The band gap of the tetragonM phase is indirect and that of the cubic phase is always direct. As pressure increases, the alloy displays the similar band-gap behaviors to PbTiO3, while different from BaTiO5, which is attributed to the different orbital contributions to the valence bands. Our calculated results are in good agreement with the available data.

关 键 词：of in is PBT BA First-Principles Investigations of Pb on 

分 类 号：TM221[一般工业技术—材料科学与工程]