Spin tuning in magnetically coupled double quantum wells

A variety of ZnSe/Zn1-xCdxSe double quantum wells coupled by a thin Zn1-yMnySe 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.