Coupling-barrier and non-parabolicity effects on the conduction electron cyclotron effectivemass and Landé factor in GaAs double quantum wells

Abstract

We have performed a theoretical study of the effects of the non-parabolicity and couplingbarrier in between GaAs quantum wells on the conduction electron cyclotron effective massand Landé factor under the action of a growth-direction applied magnetic field. Numerical calculationsare performed within the effective mass approximation and taking into account thenon-parabolicity effects for the conduction-band electrons, by means of the Ogg–McCombeeffective Hamiltonian. The system consists of two GaAs quantum wells connected by aGa1 − xAlxAs barrier andsurrounded by Ga1 − yAlyAs material. We have found that both the factor and the cyclotron effective mass are sensitive to the coupling strength, that is theheight and width of the barrier in between the GaAs quantum wells. This behavior issimilar for every Landé factor and the cyclotron effective mass calculated for different Landau levels. It isnoticeable that the splitting between the and cyclotron effective mass increases with the central barrier width and the growth-directionapplied magnetic field. As in a single quantum well, we found that the electron Landé factor increases with the growth-direction applied magnetic field, comparingquite well with the experimental reports, and that the magnetic fieldplays an important role in decoupling the quantum wells of the system.Additionally, we have studied the electron cyclotron effective mass and Landég factor as functions of the Landau levels, depending on the non-parabolicity. From thisresult one can infer that their population must be taken into account for a complete studyof the band parameters as has been proposed in previous works. The present theoreticalresults are in very good agreement with previous experimental reports in the limitinggeometry of a single quantum well.