Effects of size quantization in the spectra and Γ − M transitions in (GaAs)m(AlAs)n(001) superlattices

Based on the pseudopotential method and the phenomenological model of coupling forces, electron scattering by short-wavelength phonons in the conduction band of superlattices (GaAs)m(AlAs)n with thin layers (n, m ≤ 10) is studied. Intervalley deformation potentials for transitions between the lower states of the Γ and M valleys of superlattices, which are analogs of the sphalerite transitions of Γ̲−X̲ and X̲−X̲̃, are calculated. The intensity of the Γ − M transitions is determined mainly by the longitudinal optical vibrations of the Al atoms and depends strongly on the mixing of the states Γ̲ and X̲. The capture of phonons and electrons in AlAs layers leads to an increase in the deformation potentials of X̲−X̲̃ transitions.