Atomic and Electronic Structure in MgO–SiO₂


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Date

2024-02-01

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Understanding disordered structure is difficult due to insufficient information in experimental data. Here, we overcome this issue by using a combination of diffraction and simulation to investigate oxygen packing and network topology in glassy (g-) and liquid (l-) MgO–SiO₂ based on a comparison with the crystalline topology. We find that packing of oxygen atoms in Mg₂SiO₄ is larger than that in MgSiO₃, and that of the glasses is larger than that of the liquids. Moreover, topological analysis suggests that topological similarity between crystalline (c)- and g-(l-) Mg₂SiO₄ is the signature of low glass-forming ability (GFA), and high GFA g-(l-) MgSiO₃ shows a unique glass topology, which is different from c-MgSiO₃. We also find that the lowest unoccupied molecular orbital (LUMO) is a free electron-like state at a void site of magnesium atom arising from decreased oxygen coordination, which is far away from crystalline oxides in which LUMO is occupied by oxygen’s 3s orbital state in g- and l-MgO–SiO₂, suggesting that electronic structure does not play an important role to determine GFA. We finally concluded the GFA of MgO–SiO₂ binary is dominated by the atomic structure in terms of network topology.

Publication status

published

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Volume

128 (4)

Pages / Article No.

716 - 726

Publisher

American Chemical Society

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Subject

Amorphous materials; Chemical structure; Liquids; Oxygen; X-rays

Organisational unit

09495 - Murakami, Motohiko / Murakami, Motohiko check_circle

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