High pressure effects on high T_(c) superconductivity: the enhancement of superconducting transition temperature by ordering

摘要

We discussed the high pressure improvement on superconducting transition temperature (T_(c)) related to the ordering at the apical oxygen layer of a high temperature superconductor (HTS). This study became available in the high pressure synthesized Sr_(2)CuO_(3+delta) superconductor with K_(2)NiF_(4) structure showing so far rarely formed partially occupied apical oxygen which also act as the dopant of the HTS. The well-defined links between T_(c) and modulated structures suggests that optimizing the ordering at apical oxygen layer outside CuO_(2) plane is a promising way to further enhance T_(c).