Wave-vector dependence of magnetic properties of excitons in ZnTe

Abstract

The magnetic properties of heavy-hole excitons in wide quantum wells of ZnTe with Zn${}_{x}$Mg${}_{1\ensuremath{-}x}$Te barriers have been studied with photoluminescence and reflectivity measurements. The exciton magnetic moments (as characterized by the $g$ values) and the diamagnetic shifts of the exciton transitions are found to depend strongly on the wave-vector component ${K}_{z}$ associated with translational motion of the exciton normal to the plane of the quantum well. The case of ZnTe differs from examples of this behavior previously reported for GaS, CdTe, and ZnSe since the ZnTe is under tensile biaxial strain, so that the heavy-hole exciton states lie higher in energy than the corresponding states of the light-hole excitons. The dependence of the magnetic properties on ${K}_{z}$ is nevertheless still in excellent agreement with the predictions of a model proposed by Smith et al. [Phys. Rev. B 78, 085204 (2008)], in which mixing of the heavy-hole 1$S$ exciton state with light-hole $\mathit{nP}$ states is found to be responsible for motion-induced changes in the internal structure of the exciton.