中文摘要：

摘要根据原子环境计算（AEC）方法计算了YBa2Cu3O6和YBa2Cu3O7晶体中各原子的局域团簇结构，并结合点群和空间群理论对比分析了YBa2Cu3O7和YBa2CusO6中各原子局域团簇结构的对称性．其对超导电性的影响。结果表明，YBa2Cu3O7-x晶体中x值的变化直接影响到CuO1-x面上Cu原子局域团簇结构的对称性，进而影响到BaO面、Cu％面的对称性。YBa2CusO7晶体中各原子局域团簇结构的对称破缺是其产生超导电性的原因。同时，根据Cu原子局域团簇结构计算得到YBa2CuaO7中cu的原子价与2．2＋相近，符合产生高Tc超导的有利条件。

英文摘要：

The atomic local cluster structures of YBa2 Cu3O7 and YBa2 Cu3 06 were calculated by the Atomic Environment Calculation （AEC） method, then the syrmraetry of the local cluster structures and the influence of that on superconductivity were conmparatively analysized combined with the point group and space group theory. The results showed that the changes ofx in YBa2 Cu3 O7-x directly affect the symmetry of the local cluster structure f Cu in the CuO1-x layer, which further affect the symmetry of the BaO and the CuO2 cluster structures. The symmetric broken of these atomic local cluster structures in YBa2Cu3O7 is the causes of superconductivity. Moreover, the atomic valences of Cu in Yga2 Cu3 07 were calculated based on the local cluster structures, the results were similar to 2.2＋, which matched the superconducting conditions of high temperature superconductor.