摘要
本文用密度泛函线性丸盒轨道原子球近似方法(DFT-LMTO-ASA)对(GaAs)_1(AlAs)_1(001)超晶格的电子结构进行了第一原理性计算。利用Lowdin微扰法在矩阵元中计入d态的影响,可使本文方法仅用阶数很小(32×32)的久期方程便可较满意地处理这个超晶格系统。计算并讨论了该超晶格的带隙,导带极小值处各本征态的分波特性以及GaAs和AlAs层间的价电子转移。我们的结果同最近用计算量大得多的从头算赝势法和完整势线性缀加平面波(FLAPW)法所得的结果进行了比较。结果表明,本文方法不仅具有合理的精度,而且有快速高效率的特点,更适于研究层数较多或结构更复杂的半导体超晶格,如(GaAs)m(AlAs)n等系统的电子结构性质。
The electronic structure of a (GaAs)1 (AlAs)1, (001) superlattice has been investigated by an ab initio self-consistenf approach-the linear muffin-tin orbital (LMTO) with the atomic sphere approximation (ASA) based on the density functional theory (DFT). The method allows one to treat this superlattice system by treating only small matrices (32×32), the sizes of which depend only on the s-and p-states, where as the d-states can be taken into account in the matrix element calculations using a lowdin perturbation technique. The band gap and the partial wave characteristic of the eigenstates at conduction band minima as well as the transfer of the valence charges between the GaAs and AlAs layers are analysed and compared with the results obtained from the ab initio pseudopotential method and the full potential-LAPW method. The results indicate that our approach not only has a reasonable accuracy but also is efficient. It can therefore be applied to study the electronic structures of the ultrathin-layered semiconductor superlattice with more complex structure, e.g. (GaAs)m(AlAs)n and so forth.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1990年第7期1135-1142,共8页
Acta Physica Sinica
基金
国家自然科学基金资助的课题
