【摘要】 本文用 Recursion 方法研究了 Al 局域替代 YBa₂Cu₃O₇中的 Cu（1）引起的电子结构变化.研究发现 Al 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、成键态的类型和强弱、晶位的原子价等.计算表明,Al 替代将导致电荷发生迁移,铜氧层内空穴减少,我们认为,这正是 Al 低浓度替代时 YBa₂Cu₃O₇超导转变温度下降的主要原因.更多还原

【Abstract】 Applying Recursion method,we have studied the change of electronic structures caused by the local substitution of Al for Cu(1) 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 the calculations,we analyze the movement of charge and believe that the decrease of hole concentration in Cu-O layers is the dominant factor in lowering the superconducting transition temperature of YBa2Cu3O7 when Al substitutes Cu in small amounts.更多还原