第一性原理研究PbTiO_3(001)晶面的原子结构和表面偶极(英文)  

First-Principles Study of Atomic Structure and Subsurface Dipoles of PbTiO_3 (001) Surfaces

作　　者：倪利红[1] 刘涌[1] 徐刚[1] 宋晨路[1] 韩高荣[1] 

机构地区：[1]浙江大学,浙江杭州310027

出　　处：《稀有金属材料与工程》2010年第S2期149-153,共5页Rare Metal Materials and Engineering

基　　金：support from the Center for Engineering and Scientific Computation of Zhejiang University and the Optical and Electronic platform of Zhejiang University National Science Park

摘　　要：采用第一性原理方法和半冻结模型研究了四方相、立方相PbTiO3的PbO和TiO2终止的(001)晶面。计算结果表明,四方相的铁电畸变束缚了表面结构的驰豫。四方相表面的净偶极背向体侧,而立方相表面的净偶极指向体侧。然而在所有涉及到的表面结构中没有观测到明显的表面诱导极化。结构稳定性分析表明PbO终止的立方相PbTiO3晶面能量最低,而立方相晶面普遍比四方相晶面稳定。而且,四方相PbTiO3不同终止面的稳定性相当,而立方相PbTiO3的PbO终止面则明显更为稳定。First-principles pseudopotential calculations were carried out to investigate the (001) surfaces of tetragonal and cubic PbTiO3. Both PbO-and TiO2-terminated surfaces were considered in a half-frozen-symmetrical model. The calculated results show that the surfaces of tetragonal and cubic PbTiO3 were different in many aspects because of the tetragonal ferroelectric distortion suppressing the surface relaxation. The net subsurface dipoles of tetragonal PbTiO3 slabs moved outward bulk. In comparison, that of cubic PbTiO3 slabs moved inward bulk. Nevertheless, there was no strong surface-induced polarization found in all investigated surface structures. The analysis of the structural stability indicates that the PbO-terminated (001) surface of cubic PbTiO3 was most energetically stable of the four considered surfaces, and the cubic PbTiO3 slabs were generally more stable than the tetragonal PbTiO3 ones. Moreover, the different terminated surfaces of tetragonal PbTiO3 have a comparable stability, while PbO-terminated surface of cubic PbTiO3 was much more energetically favorable.

关 键 词：第一性原理方法 PBTIO3 表面结构 自发极化强度 

分 类 号：O742[理学—晶体学]