钇钡铜氧超导体表面电子特性研究

Calculation of Surface Electronic States of Cuprate High Temperature Superconductors YBCO(001)

基于散射理论的格林函数方法 ,采用三近邻紧束缚模型描述超导氧化物 YBCO的体电子结构 ,对 YBCO(0 0 1)表面的 3种可能截断的铜氧表面电子结构进行了计算 .计算结果表明 :相对于体电子结构特征 ,理想截断的 Cu O表面 ,其表面电子结构和体电子结构的差别较大 ,突出表现为在费米能级附近态密度有很大减少 .相反 ,对另外两种理想截断的 Cu O2 表面 ,没有表现出这种差别 .计算给出了表面投影能带结构和表面角分辨的能级谱 ,并将这些计算结果同已有实验结果作了比较 .

A theoretical investigation on the electronic structure of YBa 2Cu 3O 7(001) surface is presented. The bulk electronic structure of YBa 2Cu 3O 7 is described by the third-neighbor tight-binding formalism, and the surface electronic structure is evaluated via an analytic scattering theoretical method. The layer density of states and the surface projected band structure of both the ideal CuO and CuO 2 terminated surface are calculated. In addition, the localized surface features and orbital properties along the surface Brillouin zone Γ-Y-S-X-Γ are discussed. The results are compared with the angle-resolved photoelectron spectroscopy studies.