New description of structural disorder in silica glass. II. Application of atomistic energy distribution analysis to pressure effects

Takada, Akira; Richet, Pascal; Ataké, Tooru

doi:10.1016/j.jnoncrysol.2010.02.009

Cited by 4 publications

(4 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After bond-breaking upon compression, rebonding occurs and new compact arrangements of Si-O are generated. The present author showed that five-fold coordination increases monotonically between 5 and 20 GPa [33]. Therefore, five-fold coordination would be the transient route which allows the bond-breaking and the rebonding to take place.…”

Section: Pressure Effects Onlymentioning

confidence: 52%

“…The diffusivity maximum is recognized clearly from 1600 K up to 2400 K under a pressure of 20 GPa. The location of the maximum suggested by the previous studies is at [30][31][32][33][34][35][36][37][38][39][40] GPa at 6000 K [4] or 20 GPa from 2100 K up to 2750 K [6]. When comparing the present with the previous study [6], a common feature is that the diffusivity maximum above the glass transition temperature gets weaker and weaker and finally disappears with the increase of temperature.…”

Section: Diffusivity and Coordination Numbermentioning

confidence: 70%

See 1 more Smart Citation

Molecular dynamics study of liquid silica under high pressure

Takada¹,

Bell²,

Catlow³

2016

Journal of Non-Crystalline Solids

Self Cite

View full text Add to dashboard Cite

Structural changes of liquid silica are investigated under high pressure by molecular dynamics simulation. It is well known that high-silica liquids display anomalous pressure-dependent behaviour in their diffusivities. The potential model, the so-called 'soft potential', is used, as it is expected to simulate the structural changes of silica at high temperature well. With increasing pressure, above the glass transition temperature, the simulated silica melt shows the so-called diffusivity maximum under a pressure of 20 GPa, as already shown by the previous studies. However, it is also found that this diffusivity maximum disappears above 2800 K. The analysis of Si coordination number suggests that the competition between the increase of five-fold and that of three-fold controls the extent of the anomaly. Secondly, the analysis of 'local oxygen packing number (LOPN)', that had been developed to investigate geometrical features in amorphous structures, is applied. In a complementary manner to the analysis of the Si coordination number, the local structure in the silica melt shows the gradual structural transformation from a low-density to high density packing on compression. Finally, a model explaining the two types of change of diffusivity in silica melt was proposed in combination with the LOPN analysis and the structon analysis that had been developed to investigate the thermal change of local structures.

show abstract

Section: Pressure Effects Onlymentioning

confidence: 52%

Section: Diffusivity and Coordination Numbermentioning

confidence: 70%

Molecular dynamics study of liquid silica under high pressure

Takada¹,

Bell²,

Catlow³

2016

Journal of Non-Crystalline Solids

Self Cite

View full text Add to dashboard Cite

show abstract

“…More recently, persistent homology has attracted attention as a novel algorithm to analyze amorphous topology based on the vacancy distribution [16][17][18]. In terms of local structural environments, descriptors such as tetrahedral order of SiO 4 [19], Q n speciation, and bond order for atoms are used to represent the shortrange coordination, while medium-range descriptors are still mostly limited to local strain [20] and potential energy [21,22].…”

Section: Introductionmentioning

confidence: 99%

“…Silica also exhibits typical nonlinear behaviors such as mechanical anomaly [30] and fragileto-strong transition of diffusion behavior [31]. These peculiar properties of silica have been studied using molecular dynamics (MD) simulations [30][31][32][33][34][35][36][37] using a plethora of interatomic potentials such as the BKS potential [38], TTAM potential [39], and others [22,30,[34][35][36]40].…”

Section: Introductionmentioning

confidence: 99%

Graph theory-based structural analysis on density anomaly of silica glass

Tan¹,

Urata²,

Yamada³

et al. 2021

Preprint

View full text Add to dashboard Cite

Understanding the structure of glassy materials represents a tremendous challenge for both experiments and computations. Despite decades of scientific research, for instance, the structural origin of the density anomaly in silica glasses is still not well understood. Atomistic simulations based on molecular dynamics (MD) produce atomically resolved structure, but extracting insights about the role of disorder in the density anomaly is challenging. Here, we propose to quantify the topological differences between structural arrangements from MD trajectories using a graphtheoretical approach, such that structural differences in silica glasses that exhibit density anomaly can be captured. To balance the accuracy and speed of the MD simulations, we utilized force matching potentials to generate the silica glass structures. This approach involves casting all-atom glass configurations as networks, and subsequently applying a graph-similarity metric (D-measure). Calculated D-measure values are then taken as the topological distances between two configurations. By measuring the topological distances of configurations in silica glass simulated structures across a range of temperatures, distinct structural features could be observed at temperatures higher than the fictive temperature. In addition to quantifying structural changes in the full simulation box, we compared topological distances between local atomic environments in the glass and crystalline silica phases. Evidence from this approach suggests that more coesite-like local structures, which are less symmetric, emerge in silica glasses when density is at a minimum during the heating process.

show abstract