Modeling the near-gap dielectric properties of strained-layer multiple quantum wells and superlattices

We have developed a comprehensive approach to the calculation of the full complex permittivity tensor of an arbitrary direct-gap strained-layer superlattice (SLS) at frequencies near the fundamental band gap. The model utilizes a combination of strain-dependent superlattice K.p and nearest-neighbor tight-binding supercell models of SLS electronic structure, which is designed to provide band structures throughout the full SLS Brillouin zone which are highly accurate near the band edges. In this work, we will provide a detailed description of our approach and results of sample calculations illustrating the effects of tensile and compressive layer strains on the polarization dependence of SLS refractive index