LaB_6电子结构及光学性质的第一性原理计算

First-principles calculation on the electronic structure and optical properties of LaB_6

采用基于密度泛函理论的第一性原理的分子动力学方法系统地计算了温度为313K时LaB6基态的电子结构、态密度和光学性质.能带结构分析表明LaB6属于导体,其价带主要由B的2p态电子构成,导带主要由La的5d,6s态电子构成,静态介电常数ε1(0)=213.7,折射率n(0)=14.803,吸收系数在可见光范围内最小波谷为21585cm?1;并利用计算的能带结构和态密度分析了LaB6的介电函数实部和虚部以及由它们派生出来的光学常数,即折射率、反射谱、吸收谱、光电导率和能量损失函数等;其理论透光率的计算得出,在紫外和近红外透光率几乎为零的情况下,对可见光仍有很高的透光率,呈"吊铃型".研究结果为LaB6在窗用隔热材料方面的应用提供了理论依据.

The electronic structure and optical properties of LaB6 have been calculated using the first-principle density function theory molecular dynamics method. The results of band structure show that LaB6 is a conductor material at 313K. The density of state of LaB6 is mainly composed of La 5d, 6s and B 2p with the static dielectric function ε1（0） of 213.7, the reflectivity n（0） of 14.803, and the minimum absorption coefficient of 21585 cm？1 in the visible range. Moreover, the complex dielectric functions, refractive index, reflection spectra, absorption spectra, optical conductivity and energy loss function of LaB6 are analyzed in terms of calculated band structure and density of state. The transmittance of LaB6 is high in the visible range, however, it is nearly equal to zero in the UV and NIR ranges. The results offer theoretical data for the application of the insulating material for use with windows.