Superconductivity without dependence on valenceelectron density in Zn doped YBCO systems

This paper reports that the YBaYBCO, simulated calculations, positron annihilation, cluster effectProject supported by the National Natural Science Foundation of China (Grant No 10647145) and The Basic Science Foundation of Henan Educational Bureau of China.7410, 7165, 3120C, 3640BThis paper reports that the YBaYBCO, simulated calculations, positron annihilation, cluster effectProject supported by the National Natural Science Foundation of China (Grant No 10647145) and The Basic Science Foundation of Henan Educational Bureau of China.7410, 7165, 3120C, 3640BThis paper reports that the YBaYBCO, simulated calculations, positron annihilation, cluster effectProject supported by the National Natural Science Foundation of China (Grant No 10647145) and The Basic Science Foundation of Henan Educational Bureau of China.7410, 7165, 3120C, 3640BThis paper reports that the YBa$_{2}$Cu$_{3 - x}$Zn$_{x}$O$_{7 - \delta }\ (x=0-0.4$) samples are researched by means of x-ray diffraction, calculations of binding energy, the positron experiments and variations of oxygen content. The results of simulated calculations, positron experiments and variations of oxygen content support the existence of cluster effect. Moreover, it is concluded that the cluster effect is an important factor on suppression of high-$T_{\rm c}$ cuprate superconductivity and the $T_{\rm c}$ does not depend on the density of valence electron directly.