Coordination-number-induced morphological structural transition in a network glass
1987; American Physical Society; Volume: 36; Issue: 15 Linguagem: Inglês
10.1103/physrevb.36.8109
ISSN1095-3795
AutoresB. Norban, D. Pershing, R. N. Enzweiler, P. Boolchand, James E. Griffiths, J. C. Phillips,
Tópico(s)Material Dynamics and Properties
ResumoM\"ossbauer electric field gradients, Raman vibrational modes, and crystallization temperatures exhibit threshold behavior near the composition x=0.20 in binary ${\mathrm{Si}}_{\mathrm{x}}$${\mathrm{Te}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ glasses. This threshold is evidence of a morphological structural change that may be driven by network connectivity or average coordination number. At x\ensuremath{\le}0.20, the network largely consists of Si-cross-linked ${\mathrm{Te}}_{\mathrm{n}}$ chain segments. At x\ensuremath{\ge}0.20, ${\mathrm{Te}}_{\mathrm{n}}$ chains reconstruct with tetrahedral Si(${\mathrm{Te}}_{1/2}$${)}_{4}$ units and nucleate a defect-ridden ${\mathrm{Si}}_{2}$${\mathrm{Te}}_{3}$-like layered molecular fragment. These fragments represent the elastically rigid domains that percolate above the threshold.
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