TY - JOUR
T1 - First-Principles Magnetic Treatment of the Uranium Nitride (100) Surface and Effect on Corrosion Initiation
AU - Sikorski, Ember L.
AU - Jaques, Brian J.
AU - Li, Lan
N1 - Publisher Copyright:
© 2021 Author(s).
PY - 2021/9/7
Y1 - 2021/9/7
N2 - The magnetic properties of uranium nitride (UN) surfaces are not well understood experimentally or computationally but they have a significant effect on UN performance as a nuclear fuel. We investigated ferromagnetic (FM), antiferromagnetic (AFM), nonmagnetic (NM), and three hybrid magnetic structures of the most stable UN surface (100). To account for electron correlation and metastability, a U-ramp was performed to an effective Hubbard U-term of 2.0 eV. FM was found to be the most energetically favorable magnetic structure. Type 1 AFM slab was optimized to a new magnetic structure consisting of (100) planes with either all spin-up electrons, all spin-down electrons, or half spin-up and half spin-down electrons on uranium atoms. After OH adsorption to simulate corrosion initiation, the AFM, FM, and NM structures yield relatively similar bond lengths but varying bond angles, adsorption energies, and electronic profiles. Partial charge density maps show varying degradation mechanisms across magnetic structures. Electron localization function reveals more charge localized to AFM uranium atoms with spin-down electrons than uranium atoms with spin-up electrons. This leads to different properties depending on if an adsorbate interacts with a spin-up or spin-down terminated AFM surface. This work supports the physical accuracy of future computational studies toward corroborating with experiments and addressing UN fuel corrosion.
AB - The magnetic properties of uranium nitride (UN) surfaces are not well understood experimentally or computationally but they have a significant effect on UN performance as a nuclear fuel. We investigated ferromagnetic (FM), antiferromagnetic (AFM), nonmagnetic (NM), and three hybrid magnetic structures of the most stable UN surface (100). To account for electron correlation and metastability, a U-ramp was performed to an effective Hubbard U-term of 2.0 eV. FM was found to be the most energetically favorable magnetic structure. Type 1 AFM slab was optimized to a new magnetic structure consisting of (100) planes with either all spin-up electrons, all spin-down electrons, or half spin-up and half spin-down electrons on uranium atoms. After OH adsorption to simulate corrosion initiation, the AFM, FM, and NM structures yield relatively similar bond lengths but varying bond angles, adsorption energies, and electronic profiles. Partial charge density maps show varying degradation mechanisms across magnetic structures. Electron localization function reveals more charge localized to AFM uranium atoms with spin-down electrons than uranium atoms with spin-up electrons. This leads to different properties depending on if an adsorbate interacts with a spin-up or spin-down terminated AFM surface. This work supports the physical accuracy of future computational studies toward corroborating with experiments and addressing UN fuel corrosion.
KW - electronic correlation
KW - phonons
KW - nuclear fuel
KW - corrosion
KW - magnetic dipole moment
KW - ab-initio molecular dynamics
UR - http://www.scopus.com/inward/record.url?scp=85114554626&partnerID=8YFLogxK
UR - https://scholarworks.boisestate.edu/mse_facpubs/496
U2 - 10.1063/5.0056904
DO - 10.1063/5.0056904
M3 - Article
SN - 0021-8979
VL - 130
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 9
M1 - 095301
ER -