Kobayashi Keita, Okumura Masahiko, Nakamura Hiroki, Itakura Mitsuhiro, Machida Masahiko, Urata Shingo, Suzuya Kentaro
CCSE, Japan Atomic Energy Agency, Kashiwa, Chiba, 277-0871, Japan.
Innovative Technology Research Center, AGC Inc., 1150 Hazawa-cho, Kanagawa-ku, Yokohama, Kanagawa, 221-8755, Japan.
Sci Rep. 2023 Nov 16;13(1):18721. doi: 10.1038/s41598-023-44732-0.
The first sharp diffraction peak (FSDP) in the total structure factor has long been regarded as a characteristic feature of medium-range order (MRO) in amorphous materials with a polyhedron network, and its underlying structural origin is a subject of ongoing debate. In this study, we utilized machine learning molecular dynamics (MLMD) simulations to explore the origin of FSDP in two typical high-density silica glasses: silica glass under pressure and permanently densified glass. Our MLMD simulations accurately reproduce the structural properties of high-density silica glasses observed in experiments, including changes in the FSDP intensity depending on the compression temperature. By analyzing the simulated silica glass structures, we uncover the structural origin responsible for the changes in the MRO at high density in terms of the periodicity between the ring centers and the shape of the rings. The reduction or enhancement of MRO in the high-density silica glasses can be attributed to how the rings deform under compression.
总结构因子中的第一个尖锐衍射峰（FSDP）长期以来一直被视为具有多面体网络的非晶材料中程有序（MRO）的一个特征，其潜在的结构起源一直是一个持续争论的话题。在本研究中，我们利用机器学习分子动力学（MLMD）模拟来探究两种典型的高密度二氧化硅玻璃中FSDP的起源：受压二氧化硅玻璃和永久致密化玻璃。我们的MLMD模拟准确地再现了实验中观察到的高密度二氧化硅玻璃的结构特性，包括FSDP强度随压缩温度的变化。通过分析模拟的二氧化硅玻璃结构，我们从环中心之间的周期性和环的形状方面揭示了导致高密度下MRO变化的结构起源。高密度二氧化硅玻璃中MRO的减少或增强可归因于环在压缩下的变形方式。
