钛原子位置对立方BaTiO3电子结构的影响

本文基于密度泛函理论(DFT)的第一原理方法,计算了Ti原子位置对BaTiO3电子结构的影响.Ti的位置变化导致晶格畸变,使电子结构发生变化;从能带结构、能态密度(DOS)、电子密度、Mulliken布居等计算结果分析表明,导带和价带主要由Ti的3d电子和O的2p电子,Ti原子位置的变化,使Ti的3d电子能量分布上移,而O的2p电子能量下移;Ti位置变化,Ti的3d电子与的sp电子形成的杂化轨道更趋向离子化,以致于使OI出现了正电荷,表明发生了的2p电子向Ti的转移;O原子电子的转移使得Ti原子在导带的3d电子能量降低,与O原子在价带的2p电子能量重叠,禁带消失;随着畸变程度提高,转移逐渐增强,使禁带宽度逐渐减小,直至完全消失.

Effects of Ti atomic location on the electronic structure of cubic BaTiO3

Based on density functional theory,the effects ofTi atomic location on the electronic structures of cubic BaTiO_3 were computed by first principle computing software CASTEP,including band structure,density of states(DOS),electronic density,Mulliken charge population.The results shows that the change of Titanium atomic location can influence the electronic structure of BTO greatly.The valued and conductive band are main comprised of 3d electrons of Ti and 2p electrons of O;The dislocation of O can results in the transition of part of O_I electron to near titanium atom;this transition make the energy of 3d electrons of Ti which composed the valued band decreased;as the dislocation increasing,the energy decreased more,and finally the energy gap vanished.