Tl_2Ba_2Ca_（n－1）Cu_nO_（2n＋4）超导体的能带结构

ENERGY-BAND STRUCTURES OF HIGH-Tc SUPERCONDUCTORS Tl_2Ba_2Ca_(n-1)Cu_nO_(2n+4)

采用ＥＨＴ近似下的紧束缚能带结构方法，从能带结构、态密度和电荷分布等方面研究了Ｔｌ＿２Ｂａ＿２ＣｕＯ＿６，Ｔｌ＿２Ｂａ＿２ＣａＣｕ＿２Ｏ＿８和Ｔｌ＿２Ｂａ＿２Ｃａ＿２Ｃｕ＿３Ｏ＿（１０）超导体系的电子结构．从２－２－０－１，２－２－１－２到２－２－２－３相，费米能级附近的态密度及穿过费米面的能带数目相应增加．解释了随着单胞中Ｃｕ－Ｏ面数目的增加，超导转变温度升高的原因．

By employing the tight-binding band-strueture treatment based on the EHT approach,the author inverqtigates the electronic structures of Tl_2Ba_2CuO_6,Tl_2Ba_2CaCu_2O_8 and Tl_2Ba_2Ca_2Cu_3O_(10) supercon-ducting phaspss from band structures,eiectronic densities of states, and electron charges. From the 2-2-0-1,2-2-1-2 to 2-2-2-3 phases both the densities of states at the Fermi level and the number ofbandc,crossing the Fermi surface increase. It is explained why the suporconducting transition tempera-ture rises as the number of Cu-O layers increases.