摘要
在EHMO近似基础上,给出了一种近似处理随机氧空隙的带结构计算模型.用此模型计算了YBa_2Cu_3O_y(6≤y≤7)的电子结构,并研究了氧含量在Y-Ba-Cu-O超导体中的作用.结果表明随着氧含量y的减少,YBa_2Cu_3O_y的带结构在y=6.5左右发生很大变化,电子态密度迅速降低.此外,研究了晶体中局部结构在电子结构中的作用,并得到了2D Cu-O_2面在Y-Ba-Cu-O系中起着关键作用的结论.
Based on the EHMO approach,an approximate band-structure treatment,which can be employed to investigate the effects of random vacancies, was suggested. By use of this treatment, the electronic structures of YBa2Cu3Oy(6≤y≤7) were calculated and the role of the oxygen content in the Y-Ba-Cu-O superconductors was studied. The result show that as the oxygen content y deceases,the band structures for YBa2Cu3Oy are greatly changed at y≈6. 5 and their electronic densities of states are de-craesed rapidly. In addition, the role of structural fractions of crystals in the electronic structures was also investigated and it is concluded that the 2D Cu-O planes play a dominant role in the Y-Ba-Cu-O superconducting systems.
基金
重庆市青年专家基金资助项目
