Volume 119, Number 5, September 2017
|Number of page(s)||7|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||21 November 2017|
Pressure-driven insulator-metal transition in cubic phase UO2
1 Science and Technology on Surface Physics and Chemistry Laboratory - P.O. Box 9-35, Mianyang 621908, China
2 Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory Upton, NY 11973, USA
3 Department of Physics, University of Fribourg - 1700 Fribourg, Switzerland
Received: 28 September 2017
Accepted: 24 October 2017
Understanding the electronic properties of actinide oxides under pressure poses a great challenge for experimental and theoretical studies. Here, we investigate the electronic structure of cubic phase uranium dioxide at different volumes using a combination of density functional theory and dynamical mean-field theory. The ab initio calculations predict an orbital-selective insulator-metal transition at a moderate pressure of ∼45 GPa. At this pressure the uranium's 5f5/2 state becomes metallic, while the 5f7/2 state remains insulating up to about 60 GPa. In the metallic state, we observe a rapid decrease of the 5f occupation and total angular momentum with pressure. Simultaneously, the so-called “Zhang-Rice state”, which is of predominantly 5f5/2 character, quickly disappears after the transition into the metallic phase.
PACS: 71.30.+h – Metal-insulator transitions and other electronic transitions / 71.27.+a – Strongly correlated electron systems; heavy fermions / 71.20.-b – Electron density of states and band structure of crystalline solids
© EPLA, 2017
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