Generation of Amorphous Silicon Dioxide Structures via Melting-quenching Density Functional Modelingстатья
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 25 ноября 2020 г.
Аннотация:Abstract—Ab initio quantum molecular dynamics simulation is used to transform a silicon dioxidecrystal into silica amorphous states. Two type of amorphous states are obtained from the meltsstabilized at temperatures well above the crystal melting point. The first type of amorphous states are obtained from the melts stabilized at comparably low temperatures of 3000 and 4000 K. These states are characterized by a perfect structure similar to those of the initial crystal and vitreous silica glass without point defects. Completely different amorphous states are obtained from the high temperature melts of 5000 and 6000 K. Structures of these amorphous states are less regular and contain point defects of silicon dioxide such as over-coordinated fivefold silicon, threefold oxygen atoms and a new silica defect 2-Bridging Oxygen Center. The latter is detected in the model of amorphous silica for the first time and it is formed by two neighbouring SiO4-tetrahedra with two common oxygen vertexes. The amorphous silica models can be useful for description of amorphous silicon dioxidefilms obtained by high energy ion-beam deposition process where a fast local melting-quenchingprocess should exist.