Raman scattering in the InSb–MnSb eutectic composite

The Raman spectra of bulk samples of the InSb–MnSb eutectic composite and its thin films produced by flash evaporation are studied. In the Raman spectra of the bulk samples, the TO and LO modes of InSb at the frequencies 179.5 and 192.4 cm$^{-1}$ and a number of peaks at the frequencies 122, 127, 167, 211, and 245.5 cm$^{-1}$, close to the available theoretical data on the phonon frequencies in MnSb, are observed. In the Raman spectra of the films, the TO mode is shifted to lower energies and corresponds to 178 cm$^{-1}$, and the LO mode is shifted to higher energies and corresponds to 196 cm$^{-1}$. The shift of the LO mode to higher frequencies in the composite with respect to the corresponding mode in InSb is apparently caused by strains at the matrix–inclusion interface and by the contribution of scattering at surface phonons to the Raman spectrum.