First principles studies of band offsets at heterojunctions and of surface reconstruction using Gaussian dual-space density functional theory

The use of localized Gaussian basis functions for large scale first principles density functional calculations with periodic boundary conditions (PBC) in 2 dimensions and 3 dimensions has been made possible by using a dual space approach. This new method is applied to the study of electronic properties of II-VI (II=Zn, Cd Hg; VI=S, Se, Te, Po) and III-V (III=Al, Ga; V=As, N) semiconductors. Valence band offsets of heterojunctions are calculated including both bulk contributions and interfacial contributions. The results agree very well with available experimental data. The p(2×1) cation terminated surface reconstructions of CdTe and HgTe (100) are calculated using the local density approximation (LDA) with two-dimensional PBC and also using the ab initio Hartree-Fock (HF) method with a finite cluster. The LDA and HF results do not agree very well.