计算混晶材料电子结构的超原胞统计法

Statistical Supercell Method for Calculating Electronic Structure of Che Mixed Crystals

提出了计算赝二元系(A_(1-x)C混晶材料任意组分电子结构的超原胞统计法,接替代格点数n选择超元胞,计算B原子数n_从零到n的所有超原胞电子结构为“样本”,结合以混晶键合性质决定的统计分布确定系统的电子结构,以(Ba_(1-x)K_)BiO_3为例,计算了x=0.2至x=0.5电子结构随组分的变化,结果表明,x>0.5的超元胞是不稳定的,费米面处总态密度TDOS(EF)随x变大而增加,与实验结果一致。

A new approach for calculating the electronic structrues of the binary alloys AnB1-n and pseudobinary alloys (AnB3-2 ).C in an any composition was prasenfod. In this method, the size of the supercell l is determined by the substituted lattice number n the electronic structure of zll sd-percells with its B atomic number from zero to n are calculated, then, the eletronic structure of miked system is determined by the statistical distribution which is rciated by the bonding properties of the mixed crystal. As an example, the composition depentence of the electronic structures of (Ba1-aKx) BiOx has been calculated in a range of x=0. 2 to 0. 5, The rasuits indicate that the supercells with x> 0. 5 are unstable and the total density of states it Fermi surface was increased with the comosition x. these results are in agrsement with the experiments.