Single antiferromagnetic MnTe (sub)monolayers in CdTe/CdMgTe quantum wells
Antiferromagnetic MnTe (sub)monolayers inserted into nonmagnetic CdTe/CdMgTe quantum wells are investigated by magneto-optical spectroscopy. In particular, the Zeeman splitting is determined from polarization dependent photoluminescence excitation experiments. Rapid thermal annealing (RTA) is applied to diffuse Mn out of the (sub)monolayer barriers into the quantum well. The resulting Mn diffusion leads to a substantial increase of the Zeeman splitting. Furthermore, the annealing induced broadening of the MnTe (sub)monolayer barrier in the well is accompanied by a decrease of the barrier height, leading to a blue shift or a red shift of the e1-hh1 transition, depending on the detailed sample structure. A comparison of the observed energy shifts with model calculations allows us to estimate the thickness of the MnTe barriers. These are found to be very close to their nominal values before annealing, regardless of the chosen MnTe band offset and effective masses.