The role of apical oxygen in superconducting cuprates

摘要

Using a structure specific three-dimensional superconducting gap function, derived for YBCO, the BCS coherence factors are evaluated. They are used to calculate the low-frequency electromagnetic response in the superconducting state and good agreement with experiment is obtained. It is found that the apex oxygen ion contributes dominantly to the low-frequency properties which have been evidenced elsewhere as favouring d-wave pairing.