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《Chinese Physics B》 2012年01期
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First-principles study of structural stability and elastic property of pre-perovskite PbTiO_3

刘涌  倪利红  任召辉  徐刚  李翔  宋晨路  韩高荣  
【摘要】:The structural stability and the elastic properties of a novel structure of lead titanate,which is named preperovskite PbTiO_3 (PP-PTO) and is constructed with TiO_6 octahedral columns arranged in a one-dimensional manner,are investigated by using first-principles calculations.PP-PTO is energetically unstable compared with conventional perovskite phases,however it is mechanically stable.The equilibrium transition pressures for changing from preperovskite to cubic and tetragonal phases are 0.5 GPa and 1.4 GPa,respectively,with first-order characteristics.Further,the differences in elastic properties between pre-perovskite and conventional perovskite phases are discussed for the covalent bonding network,which shows a highly anisotropic character in PP-PTO.This study provides a crucial insight into the structural stabilities of PP-PTO and conventional perovskite.
【作者单位】State
【关键词】elastic properties phase transition density-functional theory PbTiO_
【基金】:Project supported by the National Natural Science Foundation of China(Grant No.51002135)
【分类号】:O482.1
【正文快照】:
1.IntroductionLead titanate(PbTiO3,PTO),which undergoesa single ferroelectric transition from tetragonal phaseto cubic phase with the increase of temperature orpressure,has attracted much attention because ofits applicability to fundamental research and

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