Infrared and Raman characteristics of bulk Cd1-xMnxTe and (MnTe)m/(CdTe)n short period superlattices

• Rigid-ion-model is used to study vibrational properties of (MnTe)m/(CdTe)n SLs.
• Theory offered anisotropic optic-, acoustic-mode anti-crossing and mini-gaps.
• Berreman's method provided ωTO(Γ) and ωLO(Γ) modes of each layer in SLs.
• Raman intensity profiles of optical phonons are consistent with experiments.
• Phonon spectrum help improve electrical properties of SL-based devices.

Comprehensive results of phonon dispersions are reported for the prominent (MnTe)m/(CdTe)n superlattices (SLs) by exploiting a realistic rigid-ion-model – involving both short- and long-range Coulomb interactions. Unlike conventional methods, the study offered clear support to anisotropic optical mode behavior, confinement, acoustic-mode anti-crossing, and mini-gap formation. The conformity of simulated reflectivity/transmission spectra at oblique incidence, and the Raman intensity profiles validating experimental data, has elucidated its ability to characterize epitaxial films and SLs. Contriving the phonon energy spectrum by selecting apposite SL periods can create exciting opportunities of improving electrical/thermal properties of nanostructure based devices.