Γ-Xmixing in the miniband structure of a GaAs/AlAs superlattice

Abstract
We have studied the anisotropy in the band structure of a strongly coupled GaAs/AlAs superlattice by the application of a magnetic field. An anticrossing behavior between the Γ and X states in the superlattice dispersion is demonstrated by the presence of an energy gap in the Landau-level diagram for cyclotron motion through the layers. A simple model is developed to treat Γ-X mixing at interfaces in the envelope-function approximation and the observed mixing strength is examined in terms of theoretical predictions.