Boson peak in covalent network glasses: Isostaticity and marginal stability

Fuente: arXiv
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Main Authors: Mizuno, Hideyuki, Mori, Tatsuya, Baldi, Giacomo, Minamitani, Emi
Format: Preprint
Published: 2025
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_version_ 1866914010897580032
author Mizuno, Hideyuki
Mori, Tatsuya
Baldi, Giacomo
Minamitani, Emi
author_facet Mizuno, Hideyuki
Mori, Tatsuya
Baldi, Giacomo
Minamitani, Emi
contents The boson peak (BP) stands as a key feature in understanding glasses and amorphous materials. It directly underlies their anomalous material properties, including thermal behaviors such as excess specific heat and low thermal conductivity, as well as mechanical characteristics such as nonaffine elasticity and fragile plasticity. Despite its importance, understanding of the BP remains limited in covalent network glasses. The most promising concepts are isostaticity and marginal stability, which have been established in theories of rigidity percolation and the jamming transition. While these concepts, supported by comprehensive data, account for the BP in packing-based glasses, comparable explanations have not yet been demonstrated for covalent network glasses. Here we study silica glass, a prototypical covalent network glass, using molecular dynamics simulations. We show that the BP in silica glass is governed by near-isostatic constraints and marginal stability, supporting their universality across diverse glassy systems. Furthermore, we reveal that these principles manifest as a wavenumber-independent band in the dynamical structure factor, and we demonstrate consistency with inelastic X-ray scattering data on silica glass. Our results provide a unified, experimentally testable framework for deciphering the BP and for refining the interpretation of scattering data in amorphous materials.
format Preprint
id arxiv_https___arxiv_org_abs_2508_20481
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Boson peak in covalent network glasses: Isostaticity and marginal stability
Mizuno, Hideyuki
Mori, Tatsuya
Baldi, Giacomo
Minamitani, Emi
Disordered Systems and Neural Networks
Soft Condensed Matter
The boson peak (BP) stands as a key feature in understanding glasses and amorphous materials. It directly underlies their anomalous material properties, including thermal behaviors such as excess specific heat and low thermal conductivity, as well as mechanical characteristics such as nonaffine elasticity and fragile plasticity. Despite its importance, understanding of the BP remains limited in covalent network glasses. The most promising concepts are isostaticity and marginal stability, which have been established in theories of rigidity percolation and the jamming transition. While these concepts, supported by comprehensive data, account for the BP in packing-based glasses, comparable explanations have not yet been demonstrated for covalent network glasses. Here we study silica glass, a prototypical covalent network glass, using molecular dynamics simulations. We show that the BP in silica glass is governed by near-isostatic constraints and marginal stability, supporting their universality across diverse glassy systems. Furthermore, we reveal that these principles manifest as a wavenumber-independent band in the dynamical structure factor, and we demonstrate consistency with inelastic X-ray scattering data on silica glass. Our results provide a unified, experimentally testable framework for deciphering the BP and for refining the interpretation of scattering data in amorphous materials.
title Boson peak in covalent network glasses: Isostaticity and marginal stability
topic Disordered Systems and Neural Networks
Soft Condensed Matter
url https://arxiv.org/abs/2508.20481