| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Seaborg Institutes: Emerging Topics in Actinide Materials and Science
|
| Presentation Title |
DFT+U in Uranium Dioxide: Occupation Matrix Control and Phonons |
| Author(s) |
Shuxiang Zhou, Hao Ma, Enda Xiao, Krzysztof Gofryk, Chao Jiang, Michael E. Manley, David H. Hurley, Chris A. Marianetti |
| On-Site Speaker (Planned) |
Shuxiang Zhou |
| Abstract Scope |
UO2 remains a formidable challenge for first-principles due to the complex interplay among spin-orbit coupling, Mott physics, magnetic ordering, and crystal distortions. Here we use DFT+U to explore UO2 at 0K, incorporating all the aforementioned phenomena. The technical challenge is to navigate the metastable electronic states in DFT+U, which is accomplished using f-orbital occupation matrix control to search for the ground state. We find an unreported occupation matrix, in which the oxygen cage distortion of the 3k antiferromagnetic state is in excellent agreement with experiments, and both the spin-orbit coupling and the Hubbard U are critical ingredients. We demonstrate that only select phonon modes have a strong dependence on the Hubbard U, whereas magnetic ordering has only a small influence. We measure the phonon dispersion using inelastic neutron scattering, and our calculations show good agreement. The quantitative success of DFT+U warrants exploration of thermal transport within this level of theory. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Nuclear Materials, Computational Materials Science & Engineering, |