Ni_3V_2O_8电子结构及光学性质的理论研究

Theoretical Study of Electronic Structure and Optical Properties of Ni_3V_2O_8

采用基于密度泛函理论的第一性原理平面波超软赝势法在广义梯度近似下计算了Ni_3V_2O_8的能带结构、电子态密度及其光学性质。计算结果表明,Ni_3V_2O_8存在宽度为1.0eV的间接带隙,其费米能级附近电子有弱迁移性;费米能级附近主要为Ni d、Vd和Op轨道形成的能带,且轨道之间有较强的杂化作用。当入射光能量为2.16eV时,电子将从价带顶的Nid轨道跃迁至导带底的Op轨道;当入射光能量为3.14eV时,电子则从价带中的Vd轨道跃迁至导带中的Op轨道。Ni_3V_2O_8的吸收光谱在7.26eV处出现最强吸收峰,光学带隙为3.47eV。

The energy band structure,density of electronic states and optical properties of Ni3V2O8 were calculated by using first-principle plane-wave ultra-soft pseudo-potential method based on density functional theory with generalized gradient approximation.The results show that Ni3V2O8 has indirect band gap with a width of 1.0eV,and its electrons near Fermi energy level have weak mobility.The energy bands near Fermi level are formed with Ni d、Vdand Oporbits,and there is a strong hybridization interaction among the three orbits.When the incident photons have 2.16 eV energy,the electrons transit from Ni dorbit within the top valance bands to Oporbit within the bottom conduction bands.When the incident photons have 3.14 eV energy,the electrons transit from Vdorbit within the middle valance bands to Oporbit within the middle conduction bands.The strongest absorption peak appears at 7.26 eV in the absorption spectrum of Ni3V2O8 with an optical band gap of 3.47 eV.