摘要
在广义梯度近似(GGA)下,利用超软赝势对理想PbTiO3晶体(以下简称理想晶体)和PbTiO3的OⅠ空位晶体(以下简称OⅠ晶体)的电子云重叠布局数.态密度和能带分布等进行自洽计算.结果显示:OⅠ晶体和理想晶体相比能带朝低能方向移动;在费米面附近O原子的2p轨道和Ti原子的3d轨道存在明显杂化,这种杂化是PbTiO3晶体保持铁电性的主要原因;同时,氧空位使晶体的氧八面体发生畸变,晶体结构从P4MM变为PMM2.
Based on the generalized gradient approximation（GGA）,the overlap populations,DOS and the band structure of perfect state and the OⅠvacancy PbTiO3crystals were calculated by using of ultrasoft pseudopotentials（USP）plane wave method.The results showed that,compared with the perfect crystal,the band structure of the oxygen vacancy crystals moved to low energy,and there was an obviously orbital hybridization of 2p orbit of O atom and 3dorbit of Ti atom around the Fermi surface,this is the reason of PbTiO3keeping the ferroelectric.And,OⅠ vacancy made distortion of the octahedral,the crystal structure change to PMM2from P4MM.
出处
《天津师范大学学报（自然科学版）》
CAS
北大核心
2010年第4期41-45,共5页
Journal of Tianjin Normal University：Natural Science Edition
基金
辽宁省自然科学基金资助项目(20082192)
关键词
第一性原理
PbTiO3晶体
氧空位
布局
态密度
能带
first-principles
PbTiO3crystal
oxygen vacancy
population
density of states
band structure
