Sc替代Y-Ba-Cu-O(123)系统的Cu位对该系统电子结构的影响

本文计算了高温超导材料YBa₂Cu₂ScO₇的电子结构。对于Sc替代Cu1和Cu2晶位的两种情况都进行了研究。后者对Cu-O二维面的电子结构的影响较大,有可能破坏高温超导性。但计算表明,替代Cu1晶位的可能性要大一些。本文结果显示,Sc的成键分波轨道与其余四个3d轨道的交迭分裂约为4eV,据此可用近红外荧光实验判定在Sc-Y-Ba-Cu-O高温超导材料中,Sc究竟是替代Y晶位还是Cu晶位。关键词：

EFFECT OF Sc-Cu SUBSTITUTION ON THE ELECTRONIC STRUCTURE OF Y-Ba-Cu-O(123) SYSTEMS

The electronic structures of high T_c superconductors YBa₂Cu₂ScO₇, including two cases of Sc substituting Cul and Cu2 sites, are studied. Sc-Cu2 replacement has effects on electronic structure of Cu-O layers, which may possibly destroy the high temperature superconductivity. However, our calculations show that it is more likely for Sc to substitute Cul site. It is shown that the overlapping splitting between the major bonding partial wave of Sc and its remaining four 3d orbitals is as large as 4eV. Thus one can detect experimentally, by near infrared fluorescence, whether Sc substitute Y or Cu sites in Sc-Y-Ba-Cu-O materials.