Ti掺杂对VH_2电子结构影响的第一原理研究  

First-Principle Study of the Electronic Structure of Ti-Doped VH_2

作　　者：李荣[1] 罗小玲[1] 梁国明[1] 

机构地区：[1]重庆师范大学,重庆400047

出　　处：《稀有金属材料与工程》2011年第11期1916-1920,共5页Rare Metal Materials and Engineering

基　　金：重庆市科技攻关计划项目(CSTC2010AC4099);重庆市自然科学基金(CSTC2009BB4243);重庆市教委科学技术项目(KJ090810);电子薄膜与集成器件国家重点实验室课题(KFJJ200907)

摘　　要：采用密度泛函理论(DFT)第一性原理的平面波超软赝势方法,对Ti掺杂VH2的超晶胞体系进行了几何结构优化。结果表明,随着Ti掺杂量的增加,V1-xTixH2晶胞参数逐渐增大,体系的总能量逐渐增大,体系的稳定性逐渐减弱,有利于改善放氢性能。对V1-xTixH2(x=0,0.13,0.30,0.48,0.65,1)的电子态密度、净电荷、键级以及电子密度进行了计算和分析。计算结果表明:随着Ti掺杂量的增加,V的净电荷逐渐增加,而H的净电荷逐渐减少,V-H的离子性相互作用增强,共价性相互作用减弱;在VH2中掺杂一定量的Ti以后,V-H之间的键级增大,V-H之间的相互作用增强,从而改善吸氢性能。当Ti含量大于0.48时,V-H之间的键级反而减小,V-H之间的相互作用减弱,合金的吸氢性能降低。The super-cell system of Ti-doped VH2 was optimized by means of plane-wave pseudopotential,employing the first-principle of density functional theory（DFT）.The results show that the cell parameters of V1-xTixH2 and total energy of the system increase gradually with the increment of Ti,so the stability of the system decreases and the capability of releasing hydrogen is improved.The density of states,net charge,bond order and electronic density of V1-xTixH2（x = 0,0.13,0.30,0.48,0.65,1） were also computed and analyzed.The calculation results show that the net charge of V increases whereas that of H decreases gradually with the increment of Ti;the ionic interaction between V-H is reinforced and at the same time the valent interaction is weakened;the bond order of V-H increases,the interaction between V and H becomes stronger,and thus the capability of absorbing hydrogen is improved by adding a certain amount of Ti to VH2.However,when the content of Ti in VH2 exceeds 0.48（x0.48）,the bond order of V-H decreases,and the capability of absorbing hydrogen is decreased.

关 键 词：Ti掺杂 VH2 电子结构 第一原理计算 

分 类 号：TG139.7[一般工业技术—材料科学与工程]