INFLUENCE OF LOCAL POTENTIAL ON EXCITON SPLITTING IN HIGHLY DILUTED CD1-XMNXTE

We investigated magnetoreflectance and magnetization of highly diluted bulk Cd1-xMnxTe crystals 0.2%less than or equal to x less than or equ al to 10%. The exchange constant in terms of mean field approximation and virtual crystal approximation (the ratio of the heavy hole exciton splitting to mean spin per unit cell) was evaluated and found x-depen dent. This deviation from the mean field approximation and virtual cry stal approximation prediction is caused by the local potential introdu ced by Mn ions. We discuss the problem within a Wigner-Seitz approach and within a model of magnetic and chemical disorder based on the allo y theory.