MAGNETICALLY INDUCED SPATIAL-DISPERSION IN THE CUBIC MAGNETIC SEMICONDUCTORS CD1-XMNXTE

In the transverse geometry we have detected birefringence that is line ar in the magnetic field B and the light wave vector k in the cubic ma gnetic semiconductors Cd1-xMnxTe (0 less than or equal to x less than or equal to 0.52). The effect was found to be large, similar to 1 (deg cm(-1)T(-1)), and highly anisotropic, in contrast to the Faraday and Voigt effects. The phenomenon is represented by terms of type gamma(ij kl)B(k)k(l) in the permittivity tensor epsilon(ij) and can be describe d by two parameters, A and g. Spectral studies have shown that the nor malized parameters A/x and g/x are independent of x, i.e., the effect can be related to the Mn2+ ions. Below the edge E-g of the forbidden b and, the dispersion of A is described by a (E-g-E)(-1.4)-dependence, w hile the dispersion of g is nil. Theoretical analysis has shown that t he spectral curves for A and g can be explained by the special feature s of the dispersion laws for electrons and holes (features related to the fact that there is no inversion center) and by the dependence of t he parameters of the exchange interaction on the electron wave vector. (C) 1998 American Institute of Physics. [S1063-7761(98)01809-5].