PbTiO_3纳米晶电子结构及铁电性理论研究

Theoretical Study on Electric Structure and Ferroelectric Property of PbTiO_3 Nanocrystals

采用密度泛函方法 ,以镶嵌势能的团簇模型对 Pb Ti O3纳米晶电子结构进行了量子化学计算研究 ,得到簇模型中键长、键级及净电荷之间的变化规律 .布居分析和态密度计算结果表明 ,O原子的 2 p轨道、Ti原子的 3d轨道、Pb原子的 6s轨道和 6p轨道之间的相互作用是四方相 Pb Ti O3纳米晶体出现铁电性的重要原因 ,并计算得到不同晶粒 Pb Ti

Quantum chemistry calculations of PbTiO 3 nanocrystals were carried out by means of the cluster model via DFT DVM calculating program on which the regularity among the bond lengths, bond orders, and valance charges are drawn. The analyses of the population and the density of state (DOS) show that the interaction among 3 d of Ti, 2 p of O, and 6 s and 6 p of Pb atomic orbitals causes the dipole moment and spontaneous polarization on the axis of the crystal, which results in the appearance of ferroelectric phase, the dipole moment and the intensity of the spontaneous polarization were calculated as well.