Spin tuning in magnetically coupled double quantum wells

A variety of ZnSe/${\mathrm{Zn}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Cd}}_{\mathit{x}}$Se double quantum wells coupled by a thin ${\mathrm{Zn}}_{1\mathrm{-}\mathit{y}}$${\mathrm{Mn}}_{\mathit{y}}$Se diluted magnetic semiconductor barrier have been fabricated by molecular-beam epitaxy and probed using magneto-optical photoluminescence spectroscopy. Spin splitting of the quantum confined ground states and the resulting large luminescence polarization are observed at low temperatures on tuning the barrier potential with a magnetic field. Measurements as a function of magnetic field, barrier thickness, and temperature reveal the dependence of the spin coupling between the quantum wells on the barrier’s magnetization.