### Abstract

We discuss how concepts from rigidity percolation can be used to understand the low frequency excitations and elastic properties of network glasses like Ge_{x}As_{y}Se_{1-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 Ge_{x}se_{1-x} glasses. The floppy modes, observed in inelastic neutron scattering, disappear as 〈r〉 increases from 2 up to around 2.4.

Original language | English (US) |
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Pages (from-to) | 19-24 |

Number of pages | 6 |

Journal | Journal of Non-Crystalline Solids |

Volume | 114 |

Issue number | PART 1 |

DOIs | |

State | Published - Dec 1 1989 |

### ASJC Scopus subject areas

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

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## Cite this

*Journal of Non-Crystalline Solids*,

*114*(PART 1), 19-24. https://doi.org/10.1016/0022-3093(89)90056-2