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标题：Prediction of new thermodynamically stable aluminum oxides
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作者：Yue Liu ; Artem R. Oganov ; Shengnan Wang 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
DOI：10.1038/srep09518
出版社：Springer Nature
摘要：Recently, it has been shown that under pressure, unexpected and counterintuitive chemical compounds become stable. Laser shock experiments (A. Rode, unpublished) on alumina (Al₂O₃) have shown non-equilibrium decomposition of alumina with the formation of free Al and a mysterious transparent phase. Inspired by these observations, we have explored the possibility of the formation of new chemical compounds in the system Al-O. Using the variable-composition structure prediction algorithm USPEX, in addition to the well-known Al₂O₃, we have found two extraordinary compounds Al₄O₇ and AlO₂ to be thermodynamically stable in the pressure ranges 330-443 GPa and above 332 GPa, respectively. Both of these compounds at the same time contain oxide O²⁻ and peroxide O₂²⁻ ions, and both are insulating. Peroxo-groups are responsible for gap states, which significantly reduce the electronic band gap of both Al₄O₇ and AlO₂.