# Density-driven structural transformations in ${\mathrm{B}}_{2}{\mathrm{O}}_{3}$ glass

Abstract : The method of in situ high-pressure neutron diffraction is used to investigate the structure of B2O3 glasson compression in the range from ambient to 17.5(5) GPa. The experimental results are supplemented bymolecular dynamics simulations made using a newly developed aspherical ion model. The results tie togetherthose obtained from other experimental techniques to reveal three densification regimes. In the first, BO3 trianglesare the predominant structural motifs as the pressure is increased from ambient to 6.3(5) GPa, but there is analteration to the intermediate range order which is associated with the dissolution of boroxol rings. In the second,BO4 motifs replace BO3 triangles at pressures beyond 6.3 GPa and the dissolution of boroxol rings continuesuntil it is completed at 11–14 GPa. In the third, the B-O coordination number continues to increase with pressureto give a predominantly tetrahedral glass, a process that is completed at a pressure in excess of 22.5 GPa. Onrecovery of the glass to ambient from a pressure of 8.2 GPa, triangular BO3 motifs are recovered but, relative to theuncompressed material, there is a change to the intermediate range order. The comparison between experimentand simulation shows that the aspherical ion model is able to provide results of unprecedented accuracy atpressures up to at least 10 GPa.
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Submitted on : Wednesday, December 10, 2014 - 4:03:27 PM
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### Citation

Anita Zeidler, Kamil Wezka, Dean A. J. Whittaker, Philip S. Salmon, Axelle Baroni, et al.. Density-driven structural transformations in ${\mathrm{B}}_{2}{\mathrm{O}}_{3}$ glass. Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2014, 90 (2), pp.024206. ⟨10.1103/PhysRevB.90.024206⟩. ⟨hal-01093411⟩

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