Optical Properties of the Strained Layer Superlattices (GaAs)₆/(GaP)_m(001) (m=2, 4 and 6)

First principles calculations, by means of the full-potential linearized augmented plane wave method within the local density approximation, were carried out for the optical properties of the strained layer superlattices (GaAs)6/(GaP)m(001) (m=2, 4 and 6). The calculated imaginary part of the dielectric function agrees well with the available experimental data. The assignment of the structures and the peaks in the optical spectra and band structure transitions are investigated in detail. Our results indicate that the anisotropy in these materials is mostly due to the tensile strain in the GaP layers.