某些Al_2Cu型和CrSi_2型化合物的能带结构研究

Investigation on the Band Structures of Some Al_2Cu and CrSi_2 - type Compounds

Al_2Cu型和CrSi_2型固相过渡金属原子簇化合物M_2B(M=Mo,W),M_2Ni(M=Zr,Hf)和MGe_2(M=Nb,Ta)在低温下出现超导行为.本文采用扩展的Hückel近似下的紧束缚能带方法,计算了它们的能带结构,给出了其能带、态密度与晶体轨道重叠布居,讨论了晶体中化学键强度与超导转变温度的关系.

The solid transition - metal cluster compounds M2B (M= Mo, W) and M2Ni (M= Zr, Hf) with Al2Cu structure type and MGe2 (M = Nb, Ta) with CrSi2 structure type become superconductors under low temperatures. In this paper, the band structures of these compounds have been studied by using the tight - binding energy band method within the extended Huckel scheme. Their energy bands, densities of states and crystal orbital overlap populations are given. The relationship between the strength of chemical bonding and the superconducting transition temperatures are discussed.