Electronic properties of semiconductor Fibonacci quasi-periodic superlattices

We study the lowest conduction band and the highest valence band states of Fibonacci superlattices, formed by different slabs of AlAs and GaAs grown along the (0 0 1) direction. We employ an empirical tight-binding Hamiltonian including spin-orbit coupling together with the surface Green's function matching method. Second to sixth generation superlattices with different generating layer thicknesses have been analyzed. A selective localization of the spectral strength in the thicker GaAs slab is found for both valence and conduction band states in all the cases studied here.