铜氧化物超导体正常态禁带宽度的计算

Calculation on the Energy Gap for High- T_c Copper Oxide Superconductors at Normal State

介绍了1种近似计算氧化物禁带宽度的方法,并对高温超导铜氧化物进行了计算。结果表明,铜氧化物超导体的禁宽度E_g值大多集中在8.50～8.80eV之间。在同一体系的超导氧化物中,Cu-O层结构的变化,产生的结果是T_c随E_g的增加而减小,而在YBa_2Cu_O_y中氧含量的变化导致T_c随E_g的增加而增加。超导体中正常态的E_g值与超导电性可能存在着相关关系。氧化物中平均电离能是决定其能隙E_g值的主要因素。

A approximate method for energy gap calculation of oxides is introduced in detail, and is applied for the gap culculation of high-Tc copper oxide superconductors at normal state. It is revealed from the result that, most oxide superconductors at nomal state have the gap values within 8.50-8.80eV. In the same system, the variation of Cu-O layer structure results in the increase of Tc upon the decrease of Eg, while in YBa2Cu3Oy, the variation of oxygen content results in the increase of Tc upon the increase of Eg. Further analysis shows, the Egvalues of high- Tc oxides at nomal state have a close relationship with superconductivity, and the average ionization potential is the major factor in determining the Egvalues.