【摘要】 利用电子衍射方法发现Ｂａ的掺杂增强了Ｂｉ系２２０１相的非公度调制，即沿ｂ，ｃ方向的调制周期都明显下降。超导电性研究发现适量Ｂａ的掺杂（ｘ≤０．２）可提高２２０１相的Ｔ，但当ｘ≥０．３时，其Ｔ迅速下降，同时伴随超导相－绝缘相的转变。还利用Ｘ射线和紫外光电子能谱系统地分析了此体系的电子结构的特征，在此基础上综合地分析了该体系的非公度调制结构、电子结构与超导电性的相互关系，指出这种Ｂａ￣（２＋）对Ｓｒ￣（２＋）的同价元素的替代加剧了Ｂｉ－Ｏ层与钙钛矿层间的点阵错配，从而严重地影响了Ｃｕ－Ｏ＿２面的对称特性，Ｃｕ－Ｏ＿２面中的Ｃｕ３ｄ电子态也由此而发生改变（即Ｃｕ３ｄ电子的库仑关联趋于增强）．在Ｂａ的掺杂过程中，正是由于这种Ｃｕ３ｄ电子态的改变，２２０１相才呈现出了超导相－绝缘相的转变。更多还原

【Abstract】 Abstract In this article,it is revealed that the Ba substitution intensifies the incommens-urate modulation of the Bi-2201 phase,namely the wavelengths of the modulationalong b and c directions show obvious decrease.The study of superconductivity ofthe Ba-doped 2201 shows that the appropriate substitution of Ba for Sr（x≤0.2）can raise the T of 2201 phase,but as x exceeds 0.3,T decreases sharply,simult-aneously accompanied with the superconductor-insulator.transition In addition,thecharacteristic feature of electronic structure of the Ba-doped 2201 phase is also stu-died by use of the XPS and UPS spectra,Based on all these experimental resuits,the relation between incommensurate modulation structure.electronic structure andsuperconductivity for the Bi-2201 phase are discussed comprehensively, indicatingthat the replacement of Ba￣（2+） for Sr￣（2+） intensifies the mismatch between Bi-O layersand perovskite blocks,and the enhancement of this mismatch influences the symme-try of Cu-O₂ planes seriously,just for this reason the variation of electronic stateof Cu3d takes place（i.e .the degree of the coulomb correlation of the Cu3d electr-ons tends to be intensifled）.In the process of Ba-doping,just due to the variationof Cu3d electrons,the 2201 phase undergoes a superconducting-insulating phase tran-sltion。更多还原