Magneto-oscillations in the electroluminescence intensity of resonantly coupled GaAs-AlAs superlattices: The magnetoexciton resonance

D. Bertram; K. v. Klitzing; O. Kuhn; D. K. Maude; J. C. Portal; H. T. Grahn; K. H. Ploog

doi:10.1103/PhysRevB.56.R7084

Rapid Communication

Magneto-oscillations in the electroluminescence intensity of resonantly coupled GaAs-AlAs superlattices: The magnetoexciton resonance

D. Bertram, K. v. Klitzing, O. Kuhn, D. K. Maude, J. C. Portal, H. T. Grahn, and K. H. Ploog

Phys. Rev. B 56, R7084(R) – Published 15 September 1997

Abstract

The dependence of the electroluminescence (EL) signal from excited-state interband transitions on the applied magnetic field has been investigated for two superlattice samples. Both samples show clear oscillatory behavior of the EL intensity as a function of the perpendicular magnetic field. In the sample with a subband splitting of the lowest conduction band states above the longitudinal-optical (LO) phonon energy in GaAs, the oscillations are due to the magnetophonon effect. However, in the sample with a subband splitting below the LO-phonon energy of GaAs, two series of oscillations exist, which are assigned to a different relaxation mechanism, the magnetoexciton resonance. The intersubband scattering process is enhanced at certain magnetic-field strengths due to the scattering of free carriers by excitons.