Abstract
Iron oxide is a key compound to understand the state of the deep Earth. It has been believed that previously known oxides such as FeO and will be dominant at the mantle conditions. However, the recent observation of shed another light to the composition of the deep lower mantle (DLM), and thus understanding of the physical properties of will be critical to model the DLM. Here, we report the electronic structure and structural properties of by using density functional theory and dynamic mean-field theory. The crystal structure of is composed of and dimers, where the Fe ions are surrounded by the octahedral O atoms. We found that shows a metal-insulator transition (MIT) under high pressure. The MIT is not a Mott type but a band insulator type which is driven by the dimer bond length change. However, the correlation effect of Fe orbitals should be considered to correctly describe dimer bond length of and the MIT.
- Received 10 July 2016
- Revised 26 January 2017
DOI:https://doi.org/10.1103/PhysRevB.95.075144
©2017 American Physical Society