Floppy modes and relaxation in Ge Se1− glasses

Abstract Floppy modes and relaxation processes in the GexSe1−x glasses system are studied by vibrational methods. We report Raman spectral line shapes over a temperature range from 100 to 300 K. Normalized frequency shifts with temperature of the GeSe4/2 breathing mode and the Se–Se stretching mode depend on the Ge composition. The results are associated with the stiffness transition window in which we suggest a radical decrease of Sen (n>2) segments which could be regarded as the microscopic origin of floppy modes in the Se-containing network glasses.