Mechanical and vibrational properties of network structures

M. F. Thorpe, Y. Cai

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

We discuss how concepts from rigidity percolation can be used to understand the low frequency excitations and elastic properties of network glasses like GexAsySe1-x-t-y. When the mean coordination 〈r〉 = 2 + 2x + y is low, these materials are soft and their properties are strongly influenced by low frequency phonons. We use a bond depleted diamond lattice to mimic the coordination properties of the glass. We show that a model with only covalent forces is unstable for 〈rm〉 < 2.4, but can be stabilized by small additional forces. We calculate the elastic constants and the density of states as a function of 〈r〉. Despite the simplicity of the model, the rounded phase transition at 〈r> = 2.4 is consistent with recent experimental results involving ultrasonics and inelastic neutron scattering on Gexse1-x glasses. The floppy modes, observed in inelastic neutron scattering, disappear as 〈r〉 increases from 2 up to around 2.4.

Original languageEnglish (US)
Pages (from-to)19-24
Number of pages6
JournalJournal of Non-Crystalline Solids
Volume114
Issue numberPART 1
DOIs
StatePublished - Dec 1 1989

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry

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