LaPO_(4)和ScPO_(4)电子结构和光学性质的第一性原理研究

First principles study on electronic structures and optical properties of LaPO_(4)and ScPO_(4)

本文采用基于密度泛函理论的第一性原理平面波赝势方法,对LaPO_(4)和ScPO_(4)的能带结构、电子态密度及光学性质进行计算和分析.计算结果表明:LaPO_(4)的禁带宽度为5.646 eV,ScPO_(4)的禁带宽度为4.531 eV.LaPO_(4)晶体价带顶主要由P-3s、P-3p及O-2p态贡献,导带底主要是由La-5d态贡献;ScPO_(4)晶体价带顶主要由P-3s、P-3p及O-2p态贡献,导带顶主要是由Sc-3d态贡献.就光学性质而言,ScPO_(4)的静介电常数是2.03,比LaPO_(4)(1.92)的静介电常数大,体系极化能力较好.

The first-principles plane-wave pseudopotential method based on density functional theory is used to calculate and analyze the electron band structures,densities of state and optical properties of LaPO_(4)and ScPO_(4).The calculated results show that the band gap of LaPO_(4)is 5.646 eV and that of ScPO_(4)is 4.531 eV.The top of valence band of LaPO_(4)crystal is mainly contributed by P-3s,P-3p and O-2p states,while the bottom of conduction band is mainly contributed by La-5d state.The valence band top of ScPO_(4)crystal is mainly contributed by P-3s,P-3p and O-2p states,and the conduction band top is mainly contributed by Sc-3d states.In terms of optical properties,the static dielectric constant of ScPO_(4)is 2.03,which is larger than that(1.92)of LaPO_(4),and the polarization ability of the system is better.