Slowly Quenched, High Pressure Glassy B$_2$O$_3$ at DFT Accuracy

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Main Authors: Meher, Debendra, Avula, Nikhil V. S., Balasubramanian, Sundaram
Format: Preprint
Published: 2024
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author Meher, Debendra
Avula, Nikhil V. S.
Balasubramanian, Sundaram
author_facet Meher, Debendra
Avula, Nikhil V. S.
Balasubramanian, Sundaram
contents Modeling inorganic glasses requires an accurate representation of interatomic interactions, large system sizes to allow for intermediate-range structural order, and slow quenching rates to eliminate kinetically trapped structural motifs. Neither first principles- nor force field-based molecular dynamics (MD) simulations satisfy these three criteria unequivocally. Herein, we report the development of a machine learning potential (MLP) for a classic glass, B$_2$O$_3$, which meets these goals well. The MLP is trained on condensed phase configurations whose energies and forces on the atoms are obtained using periodic quantum density functional theory. Deep potential MD (DPMD) simulations based on this MLP accurately predict the equation of state and the densification of the glass with slower quenching from the melt. At ambient conditions, quenching rates larger than 10$^{11}$ K/s are shown to lead to artifacts in the structure. Pressure-dependent X-ray and neutron structure factors from the simulations compare excellently with experimental data. High-pressure simulations of the glass show varied coordination geometries of boron and oxygen, which concur with experimental observations.
format Preprint
id arxiv_https___arxiv_org_abs_2409_14949
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Slowly Quenched, High Pressure Glassy B$_2$O$_3$ at DFT Accuracy
Meher, Debendra
Avula, Nikhil V. S.
Balasubramanian, Sundaram
Chemical Physics
Disordered Systems and Neural Networks
Materials Science
Modeling inorganic glasses requires an accurate representation of interatomic interactions, large system sizes to allow for intermediate-range structural order, and slow quenching rates to eliminate kinetically trapped structural motifs. Neither first principles- nor force field-based molecular dynamics (MD) simulations satisfy these three criteria unequivocally. Herein, we report the development of a machine learning potential (MLP) for a classic glass, B$_2$O$_3$, which meets these goals well. The MLP is trained on condensed phase configurations whose energies and forces on the atoms are obtained using periodic quantum density functional theory. Deep potential MD (DPMD) simulations based on this MLP accurately predict the equation of state and the densification of the glass with slower quenching from the melt. At ambient conditions, quenching rates larger than 10$^{11}$ K/s are shown to lead to artifacts in the structure. Pressure-dependent X-ray and neutron structure factors from the simulations compare excellently with experimental data. High-pressure simulations of the glass show varied coordination geometries of boron and oxygen, which concur with experimental observations.
title Slowly Quenched, High Pressure Glassy B$_2$O$_3$ at DFT Accuracy
topic Chemical Physics
Disordered Systems and Neural Networks
Materials Science
url https://arxiv.org/abs/2409.14949