First-principles study of UO$_2$ lattice thermal-conductivity: A simple description
| Autor: | Sheykhi, Samira, Payami, Mahmoud |
|---|---|
| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Iran J Sci Technol Trans Sci (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1007/s40995-020-00927-y |
| Popis: | Modeling the high-$T$ paramagnetic state of bulk UO$_2$ by a non-spin-polarized calculation and neglecting the Hubbard-U correction for the $f$ electrons in U atoms, the lattice thermal conductivity of bulk UO$_2$ is investigated by the exact solution of the Boltzmann transport equation for the steady-state phonon distribution function. The results show that TA branches corresponding to U-atoms vibrations have the largest lifetimes and therefore have dominant role in thermal conductivity, while the optical branches corresponding mainly to O-atoms vibrations have the shortest lifetimes. Using this simple model, our results for the thermal conductivity show a very good agreement with the experiments. The calculations are repeated for bulk UO$_2$ with different U-235 concentrations of 3\%, 5\%, 7\%, and 20\%, and the results show a small decrease of thermal conductivity which arise from scattering of phonons by impurities. Comment: RevTeX, 8 pages, 10 pdf figures |
| Databáze: | arXiv |
| Externí odkaz: |
|