skip to main content

DOE PAGESDOE PAGES

Title: Phase equilibria in the U-Si system from first-principles calculations

Density functional theory calculations have been used with spin-orbit coupling and on-site Coulomb correction (GGA + U) methods to investigate the U-Si system. Structural prediction methods were employed to identify alternate stable structures. Convex hulls of the U-Si system were constructed for each of the methods to highlight the competing energetics of various phases. For GGA calculations, new structures are predicted to be dynamically stable, but these have not been experimentally observed. When the GGA + U (U eff > 1.3 eV) method is considered, the experimentally observed structures are predicted to be energetically preferred. Phonon calculations were used to investigate the energy predictions and showed that the use of the GGA + U method removes the significant imaginary frequencies observed for U 3Si 2 when the correction is not considered. In conclusion, total and partial electron density of states calculations were also performed to understand the role of GGA + U methods and orbitals on the bonding and stability of U-Si compounds.
Authors:
 [1] ;  [1] ; ORCiD logo [2] ;  [3] ; ORCiD logo [4]
  1. Univ. of South Carolina, Columbia, SC (United States). Dept. of Mechanical Engineering, Nuclear Engineering Program
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Westinghouse Electric Sweden, Vasteras (Sweden)
  4. Missouri Univ. of Science and Technology, Rolla, MO (United States). Physics Dept.
Publication Date:
Report Number(s):
LA-UR-16-21445
Journal ID: ISSN 0022-3115
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 479; Journal Issue: C; Journal ID: ISSN 0022-3115
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 36 MATERIALS SCIENCE
OSTI Identifier:
1458932
Alternate Identifier(s):
OSTI ID: 1359427

Noordhoek, Mark J., Besmann, Theodore M., Andersson, Anders David Ragnar, Middleburgh, Simon C., and Chernatynskiy, Aleksandr. Phase equilibria in the U-Si system from first-principles calculations. United States: N. p., Web. doi:10.1016/j.jnucmat.2016.07.006.
Noordhoek, Mark J., Besmann, Theodore M., Andersson, Anders David Ragnar, Middleburgh, Simon C., & Chernatynskiy, Aleksandr. Phase equilibria in the U-Si system from first-principles calculations. United States. doi:10.1016/j.jnucmat.2016.07.006.
Noordhoek, Mark J., Besmann, Theodore M., Andersson, Anders David Ragnar, Middleburgh, Simon C., and Chernatynskiy, Aleksandr. 2016. "Phase equilibria in the U-Si system from first-principles calculations". United States. doi:10.1016/j.jnucmat.2016.07.006. https://www.osti.gov/servlets/purl/1458932.
@article{osti_1458932,
title = {Phase equilibria in the U-Si system from first-principles calculations},
author = {Noordhoek, Mark J. and Besmann, Theodore M. and Andersson, Anders David Ragnar and Middleburgh, Simon C. and Chernatynskiy, Aleksandr},
abstractNote = {Density functional theory calculations have been used with spin-orbit coupling and on-site Coulomb correction (GGA + U) methods to investigate the U-Si system. Structural prediction methods were employed to identify alternate stable structures. Convex hulls of the U-Si system were constructed for each of the methods to highlight the competing energetics of various phases. For GGA calculations, new structures are predicted to be dynamically stable, but these have not been experimentally observed. When the GGA + U (Ueff > 1.3 eV) method is considered, the experimentally observed structures are predicted to be energetically preferred. Phonon calculations were used to investigate the energy predictions and showed that the use of the GGA + U method removes the significant imaginary frequencies observed for U3Si2 when the correction is not considered. In conclusion, total and partial electron density of states calculations were also performed to understand the role of GGA + U methods and orbitals on the bonding and stability of U-Si compounds.},
doi = {10.1016/j.jnucmat.2016.07.006},
journal = {Journal of Nuclear Materials},
number = C,
volume = 479,
place = {United States},
year = {2016},
month = {7}
}