The boson peak in Raman spectra of AsxS1-x glasses

The Raman spectra of AsxS1 - x glasses with x < 40 at % (Z < 2.4) have been studied in a wide temperature range (20-300 K). A well resolved boson peak is observed in the low-frequency portion of the spectrum, not withstanding the appearance of floppy modes in the glasses under study. It is shown that the boson peak is characterized by two parameters: intensity and the peak position. A comparison of the intensity variation for the boson peaks indicates that the degree of disorder increases as x decreases. This effect is caused by floppy modes in the glass network and by sulfur phase separation. Studies of reduced boson peaks in the Raman spectra of AsxS1 - x glasses confirms the theoretical assumption that the shape of the peaks is independent of composition and temperature. (c) 2005 Pleiades Publishing, Inc.