Vibrational modes in the athermally photoinduced fluidity regime of glassyAs2S3 - art. no. 214203

A subbandgap light scattering investigation of vitreous arsenic trisulfide, v-As2S3, fibers subjected to external elongation stress has been undertake n in order to elucidate the photoinduced fluidity effect [H. Hisakuni and K . Tanaka, Science 270, 974 (1995)] in a microscopic scale. Orientational ch anges in the short-range order (intramolecular vibrations) caused by the pr esence of the illuminating visible light are detected. Subtle but noteworth y alterations are revealed in the intermediate range order, manifested as t he increase of the magnitude and the modification of the frequency dependen ce of the depolarization ratio-in the low frequency part of the spectrum-as a function of the applied stress. The results are discussed alongside with old and recent structural models that have been employed to account for li ght-induced changes in amorphous semiconductors and low-energy modes in amo rphous solids.