@article{f4a54182f44f4f31a80c3efad8e60e31,
title = "First evidence for vibrational excitations of large atomic clusters in amorphous semiconductors",
abstract = "Raman and depolarization spectra of GeSe2 alloyed with Se or As2Se reveal a sharp vibrational doublet, only one component of which can be attributed to a vibrational excitation of the GeSe2 local atomic cluster. The composition dependence of the intensity and polarization of the second feature identify it as an excitation involving a substantially larger cluster with high symmetry. The large cluster is a ring of Ge atoms inter-connected through single Se atoms.",
author = "Nemanich, {R. J.} and Solin, {S. A.} and G. Lucovsky",
note = "Funding Information: GeSez is one member of a large class of glass-forming compounds including Si02 which exhibit a chemically ordered phase characterized by a corner-connected network of XY, tetrahedral elements.5 The frequencies and symmetries (or depolarization) of the dominant bond-stretching spectral features of such compounds can be understood quantitatively on the basis of a valence force field (VFF) analysis of the XY, unit.6 For XY, type glasses the VFF analysis predicts one symmetric bond stretching mode that would be Raman active and strongly polarized, but the Raman spectrum of GeSe, (x = 1 spectrum of Fig. 1) exhibits two strong polarized modes in the bond stretching regime. By alloying GeSe? we can dilute and decouple the GeSe4 tetrahedra and thereby identify not only the modes of the tetrahedra but also modes that arise from larger structural units. Figures 1 and 2 show the Raman and depolarization{\textquoteright} * Research at the University of Chicago supported by ERDA. It has also benefited from the general support of the Materials Research Laboratory by the NSF.",
year = "1977",
month = jan,
doi = "10.1016/0038-1098(77)90185-5",
language = "English (US)",
volume = "21",
pages = "273--276",
journal = "Solid State Communications",
issn = "0038-1098",
publisher = "Elsevier Limited",
number = "3",
}