BaSe的准粒子能带结构

运用标准的准粒子GW方法重新考察了BaSe的准粒子能带结构.为便于比较，同时计算了局域密度近似(LDA)和广义梯度近似(GGA)下的能带.结果表明，LDA和GGA方法都不能准确描述这个材料的带隙.与实验测量值对比，其误差分别达到39.9%和32.6%.GW准粒子能带的结果则可以对其带隙作出大幅度的修正，得到与实验测量相当符合的理论结果.与已有的计算结果不同，B1结构BaSe准粒子能带具有Γ点直接带隙特性，表明在Ba价电子组态中考虑4d电子的作用至关重要. 关键词： BaSe GW 能带结构 带隙

GW quasiparticle band structure of BaSe

The electron structure of barium's VIB compound is not clearly known yet. The main problem is that not only the band gap calculated by using DFT (density functional theory) has a large discrepancy compared with experimental results,but also the theoretical values of band gap are inconsistent for different research groups.In order to resolve these problems, this paper makes the Green function-screened coulomb interaction quasiparticle theory(GW) calculation to get the quasiparticle band structure of BaSe.For the convenience of comparison, it deals with the systematic calculation of the energy band of BaSe by using the methods of local density approximation (LDA) and the generalized gradient approximation(GGA). The result shows that the methods LDA and GGA can not describe the band gap of the material accurately, because the calculation errors are as high as 39.9% and 32.6%, respectively. However, the result of quasiparticle band gap by GW improves the band gap value greatly and give the theoretical result which agrees with the experimental measurement. At variance with the known result, BaSe of quasiparticle band gap in the B1 structure is shown to have a direct gap at the Γ-point in the present paper,which indicates that it is important to take into account the 4d electronic effect in the valence electron configuration of barium.