Localized excitations in diluted magnetic Cd1-xMnxTe semiconductor ternary alloys and CdTe/Cd1-xMnxTe superlattices

In terms of a long-wavelength optical response theory, we have analysed the far-infrared reflectivity spectra of Cd1-xMnxTe ternary alloys and predicted s- and p-polarized reflectance in CdTe/Cd1-xMnxTe thick multiple heterostructures. Lattice dynamics of bulk cubic CdTe, MnTe; folded phonons and anisotropy of optical modes in CdTe/Cd1-xMnxTe [001] SLs are investigated using a realistic rigid-ion-model (RIM). The short-range forces in CdTe and MnTe materials are optimized by incorporating neutron scattering and transformed Raman data of phonons and elastic constants. The long-range Coulombic forces are evaluated exactly by Ewald summation method. In CdTe/Cd1-xMnxTe SLs, the influence of composition and disorder in Cd1-xMnxTe ternary alloys is described within a modified random-element iso-displacement scheme generalized to layered structures with arbitrary wavevectors and composition profiles. Theoretical results are compared and discussed with the existing far infrared and Raman scattering data. (C) 1999 Elsevier Science B.V. All rights reserved.