First Principle Self-Consistent Pseudopotential Calculation on the Electronic Structure of (InAs)₁(GaAs)₁ Superlattice

The band structure of the (InAs)₁(GaAs)₁ strained superlattice is calculated by the self-consistent pseudopotential method. The results show that the (InAs)₁(GaAs)₁ is a direct-gap superlattice. With the local density approximation, the band gap calculated with the room temperature lattice constants is 0.43eV, and the corrected value is 0.91eV, in agreement with experimental results. Because of the lattice mismatch between InAs. and GaAs layers, the three-fold degenerate energy level at the top of valence band splits into two levels with a spacing of 0.29eV. The splitting of energy level is also estimated and explained using the effective-mass theory.