Raman scattering from magnetic excitations in diluted magnetic semiconductors (invited)

Abstract

Alloys of II–VI semiconductors with magnetic semiconductors like MnS, MnSe, MnTe—the diluted magnetic semiconductors—occur in a homogeneous phase with the zinc blende or wurzite structure, over a large composition range. Thanks to the presence of the substitutional Mn++ and in turn, a strong Mn++–Mn++ and Mn++–band electron exchange interaction, these alloys exhibit striking magnetic properties. Raman scattering is a powerful technique for their investigation. This is illustrated with results on Cd1−xMnxTe which exhibits (1) Raman lines associated with ΔmS=±1 as well as ΔmS=±2 paramagnetic transitions within the Zeeman multiplet of the S=5/2 ground state of Mn++ (2) the paramagnetic transitions in combination with LO-phonons (3) spin-flip transition of a bound electron (4) evolution of the paramagnetic line of Mn++ into the high frequency component of the magnon line split into a doublet by the magnetic field. The magnon line has been studied as a function of temperature, composition, and magnetic field.