应变层超晶格(InAs)_n(InP)_n(001)电子结构的LMTO计算

ELECTRONIC STRUCTURE OF STRAINED SUPERLATTICES (InAs)_n(lnP)n(00l):ab initio LMTO CALCULATION

基于Linearized-Muffin-Tin Orbitals(LMTO)能带方法,采用内部求和计入空d轨道的处理,对(InAs)_n(InP)_n(001),(n=1,2,3)应变层超晶格的电子结构进行了第一性原理计算。得出了其能带结构,态密度分布(对n=1)。考察了In 4d轨道对能带计算的影响,并采用冻结势方法求出了(InAs)_n(InP)_n(001),(n=1,2,3)的价带边不连续值△E_v。结果表明在该系统中,体性质在紧靠界面的分子层中就得到恢复。本文得出的(InAs)_1(InP)_1(001)系统的价带结构与大计算量的线性缀加平面波(FLAPW)方法的结果相当一致。本义得出的△E_v值与用芯态能级和平均静电势作为参考能级的FLAPW计算以及实验值有很好的一致性。由于本文方法只需很小的计算量且有较好的精度,对于多层应变层超晶格电子结构的研究将是有效的方法。

The electronic structure of strained superlattices (SLS) (InAs)n(InP)n(001) are calculated with the Linearized-Muffin-Tin Orbitals (LMTO) band structure method in which the higher energy unoccupied d orbitals are treated by internal summation approach. The effects of In 4d orbitals on band structures are investigated. The valence band offsets (ΔEV) at SLS's are determined by a frozen-potential approach. The results show the bulk-like property is almost recovered in the molecular layers next to the interfaces. The band structure of (InAs)1 (InP)1(001) given by the present work is well consistent with those given by more elaborate FLAPW calculation. The ΔEv values determined by the present calculation are in good agreement with those from XPS measurement and FLAPW method in which the core level or the macroscopic average potentials is used as a reference level. The small calculation effort and the satisfactory precision justify the present method as a very effective means for studying the electronic structures of multi-layers SLS.