价电子密度与Y123铜氧超导电性关系研究

Reflections of Superconductivity Unrelated to Valence Electron Density in Metal Doped Y123 Cuprates

摘要:

通过X射线衍射、超导电性测试、氧含量变化、正电子湮没以及理论计算等方法， 系统研究了金属离子掺杂的YBa2Cu3-x(Fe, Co, Al)xO7-δ (x=0.0~0.5) 铜氧超导体的超导电性，为了比较也一并讨论了Zn掺杂样品的实验和理论结果。研究表明，超导转变温度Tc与样品中价电子密度无直接关联，与Hall实验揭示的Tc与空穴载流子浓度关系有同样结论，表明电声耦合机制在铜氧超导体中失效。因此，无论是空穴配对还是电子配对， 仅仅是实现超导态的前提， 并非其真正的决定因素。如果铜氧超导微观机制依然沿袭“电声耦合”理念很可能误入歧途。

Abstract:

Through XRD, the superconductivity tests, the positron annihilation technology, oxygen content variation and theoretic calculations, the superconductivity of the high-Tc cuprates YBa2Cu3-x (Fe, Co, Al)xO7-δ (x=0.0~0.5) was investigated, and Zn doped cuprates were also mentioned for comparison. The results and theoretic calculations support congruously that the superconducting transition temperature Tc is unrelated to the density of valence electron, and the same conclusion is from Hall Effect experiments that the Tc is not related with the carrier concentration of oxygen hole. Thus it is concluded either hole pairing or electron pairing is only a precondition but is not a real decisive factor that superconducting state occurs. If still following “electric-phonon coupling” the microcosmic mechanism of high-Tc cuprates will go astray.