Ferromagnetism in II–VI-based semiconductor structures

Experimental results obtained on Zn1−xMnxTe layers and Cd1−xMnxTe quantum wells are surprisingly well understood in the framework of a mean field model of the carrier-induced ferromagnetic transition, provided the real structure of the valence band is properly taken into account. Here we put the emphasis on effects leading to deviations from the standard model: RKKY oscillations in Zn1−xMnxTe when the Mn concentration is not high enough with respect to the carrier density, electronic disorder and localization at low carrier density in Zn1−xMnxTe epilayers and Cd1−xMnxTe quantum wells. Importantly, the modulation of magnetic properties through modulation of the carrier density, either optically or using the electric potential in a pin diode, is demonstrated.