用线性丸盒轨道原子球近似超元胞法计算(Ba_(1-x)K_x)BiO_3立方超导相(x=0.25,0.5,0.75)的电子结构

Abstract

【中文摘要】 用线性丸盒轨道原子球近似(LMTO-ASA)超元胞法计算(Ba_(1-x)Kx)BiO_3立方超导相x=0.25与x=0.5的电子结构,作为对照同时计算立方结构x=0.75的电子结构。计算结果表明,用超元胞法可以得到比“刚带近似”较精确的电子结构参数。给出Fermi面上的能带参数随组分的变化趋势。讨论了不等价的氧原子与周围金属原子价轨道的杂化特征。 【英文摘要】 Electronic structure for ordered Bal-xK3BiO3 alloys has been calculated with a supercell LMTO method. The results indicate that the band parameters obtained from this approach are more accurate than that from rigid-band approximation. The composition dependence of the band parameters at Fermi surface is given. The hybrid feature of the valence orbitals between the inequivalent oxygen and metal atoms is discussed.