Zn局域替代YBa2Cu3O7中的Cu引起的电子结构变化

本文用Recursion方法研究Zn局域替代Ba₂Cu₃O₇中的Cu(2)引起的电子结构变化。研究表明,Zn的替代对替代晶位及其近邻的电子结构性质有重要影响。这些性质包括分波态密度、成键态的类别和强弱、晶位上原子的原子价等。计算结果的分析指出,Zn替代将导致电荷发生迁移,使CuO₂层层内的空穴减少。我们认为,电荷分布发生的这种变化是Zn低浓度替代时YBa₂Cu₃O_{7 关键词：}

CHANGE OF ELECTRONIC STRUCTURES CAUSED BY LOCAL SUBSTITUTION OF Zn FOR Cu IN YBa2Cu3O7 MATERIAL

Using Recursion method, we have studied the change of electronic structures caused by local substitution of Zn for Cu(2) in YBa₂Cu₃O₇ material. It is found that the substitution has important effect on the properties of the substituted site and its neighbours, which include the partial wave densities of states, the type and strength of bonds, and the atomic valence of sites. On the basis of calculations, we analyze the mo ement of charge and believe that the decrease of hole concentration in CuO₂ layers is the dominant factor in lowering the superconducting transition temperature of YBa₂Cu₃O₇ when Zn substitutes Cu in small amounts.