Hidden in-plane anisotropy of interfaces in Zn(Mn)Se /BeTe quantum wells with a type-II band alignment.

Circularly and linearly polarized radiation due to spatially indirect optical transitions is studied in semimagnetic (Zn,Mn)Se/BeTe and nonmagnetic ZnSe/BeTe quantum-well structures with a type-II band alignment. Because of the giant in-plane anisotropy of the optical matrix elements related to a particular interface, complete spin orientation of photocarriers induced by magnetic fields leads not to purely circular but instead to elliptical polarization of the luminescence. From comparison between theory and experiment the parameter of optical anisotropy of a ZnSe/BeTe interface is evaluated. The developed theoretical approach can be applied for the large class of nanostructures revealing optical anisotropy.