Magnetic Field-Induced Type-I Type-II Transition in (ZuMu)Se/(ZaBe)Se Spin Superlattices

Abstract : We have performed a magnetooptical study on spin superlattice structures fabricated on the basis of (ZnMn)Se/(ZnBe)Se. The band alignment of a Zn(0.91)Mn(0.09)Se/ Zn(0.972)Be(0.028)Se superlattice was found to undergo a type-I to type-Il transition for one of the exciton spin component. This spin superlattice formation manifests itself in an asymmetric Zeeman splitting of a spatially direct exciton resulting from a spin dependent change of the exciton binding energy. A pronounced broadening of the spatially direct exciton in reflectance and photoluminescence excitation spectra was observed when scattering in the (ZnBe)Se barriers becomes possible.