Raman spectra of Pb1−xMnxTe alloys

The influence of Mn concentration on Raman spectra of Pb1−xMnxTe (x ≤ 0.1) crystals at room temperature in 15-200 cm−1 spectral range were investigated. Well-resolved peaks at 129 and 146 cm−1 were observed for all samples. These modes originated from the vibrations of TeO2. Other modes appeared at about 53 and 104 cm−1 when x = 0.02. The intensity and position of these modes increases when Mn concentration increases. The analysis showed that off-centre Mn ions in Pb1−xMnxTe play important role in the Raman activity. The model of phonon behaviour based on Genzel's model was developed. It was found that the long wavelength optical phonon modes of these mixed crystals showed an intermediate one-two mode behaviour. Also, structural properties of the samples were observed by optical microscopy after chemical polishing and etching, and by X-ray diffraction.