Observation of Giant Magnetic Linear Dichroism in (Ga,Mn)As

Giant magnetic linear dichroism (MLD) is observed in the ferromagnetic semiconductor Ga_0.98Mn_0.02As. The contribution to this effect induced by the spontaneous magnetization can be clearly identified by azimuthal dependencies. The spectral dependence of the effect in the range from 1.4 to 2.4 eV shows that the MLD induced by the spontaneous magnetization is strongly enhanced for excitations from the electronic states that are responsible for the ferromagnetism in this material. This spectral sensitivity and the size of the effect makes MLD a powerful tool for the study of (III,Mn)V alloys and similar novel ferromagnetic semiconductors.