Prediction of an U2S3-type polymorph of Al2O3 at 3.7 Mbar.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 18451030.
- Also identified by DOI 10.1073/pnas.0711925105 and PMC identifier 2373319.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
We predict by first principles a phase transition in alumina at approximately 3.7 Mbar and room temperature from the CaIrO(3)-type polymorph to another with the U(2)S(3)-type structure. Because alumina is used as window material in shock-wave experiments, this transformation should be important for the analysis of shock data in this pressure range. Comparison of our results on all high-pressure phases of alumina with shock data suggests the presence of two phase transitions in shock experiments: the corundum to Rh(2)O(3)(II)-type structure and the Rh(2)O(3)(II)-type to CaIrO(3)-type structure. The transformation to the U(2)S(3)-type polymorph is in the pressure range reached in the mantle of recently discovered terrestrial exoplanets and suggests that the multi-megabar crystal chemistry of planet-forming minerals might be related to that of the rare-earth sulfides.