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- Title
Prediction of new thermodynamically stable aluminum oxides.
- Authors
Liu, Yue; Wang, Shengnan; Zhu, Qiang; Oganov, Artem R.; Dong, Xiao; Kresse, Georg
- Abstract
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 Laser shock experiments (A. Rode, unpublished) on alumina (Al2O3) have shown non-equilibrium decomposition of alumina with the formation of free Al and a mysterious transparent phase.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.
- Subjects
ALUMINUM oxide; CHEMICAL stability; PHOTONIC band gap structures; BAND gaps; PHASE transitions; PRESSURE measurement
- Publication
Scientific Reports, 2015, p9518
- ISSN
2045-2322
- Publication type
Article
- DOI
10.1038/srep09518