不同氧含量的YBa2Cu3O7-δ第一原理的计算研究

First-Principles Calculation of YBa_2Cu_3O_(7-δ) in Different Oxygen Content

应用密度泛函理论中的BLYP交换关联泛函,结合YBa2Cu3O7-δ(0.07≤δ≤0.91)原子团簇模型,计算其不同氧含量下的电子结构,研究其在超导态和非超导态下最高占据态的分子轨道,计算了YBa2Cu3O7-δ(0.07≤δ≤0.62)正交相晶格能与氧含量的关系。计算结果表明YBa2Cu3O7-δ(0.07≤δ≤0.91)在不同氧含量下能隙值存在三个平台;CuO2面电子结构具有明显的dx2-y2对称性;正交相的晶格能随氧含量的增加而增大。

With a cluster model of YBa2Cu3O7-δ（0.07 ≤δ≤ 0.91）, the hybrid density functional BLYP has been used to study the electronic structure, HOMO the superconducting and non-superconducting phases. The crystal lattice energy of the superconducting phase has been calculated in different oxygen content. The results show that 3 steps in YBa2Cu3O7-δ（0.07 ≤δ≤ 0.91）energy-gap, dx2-y2 symmetry in the electronic structure of CuO2 planes, and the orthorhombic crystal lattice energy increase with oxygen content.