First-principles Computational Study of Defect Clustering in Solid Solutions of ThO2 with Trivalent Oxides
- Univ. of California, Davis, CA (United States); Univ. of California, Berkeley, CA (United States)
- Univ. of California, Davis, CA (United States)
- Univ. of California, Berkeley, CA (United States); Univ. of California, Davis, CA (United States)
The energetics of mixing and defect ordering in solid solutions of fluorite-structured ThO2 with oxides of trivalent cations (Sc, In, Y, Nd, and La) are investigated by electronic density-functional theory (DFT). Through DFT calculations of structures enumerated by lattice-algebra techniques, we identify the lowest energy patterns for defect clustering for four separate dopant concentrations. The most stable structures are characterized by a repulsive interaction between nearest-neighbor vacancies on the oxygen sublattice. The enthalpies of formation with respect to constituent oxides are positive for all dopants considered, and show a tendency to decrease in magnitude as the size and electronegativity of the trivalent dopant decrease. Due to the small positive formation enthalpies and low oxygen-vacancy binding energy with La dopants, La O3 -ThO2 solid solutions are predicted to have relatively high ionic conductivities relative to those for the other aliovalent dopants considered. Our results are compared with those for the more widely studied ZrO2 and CeO{sub 2} fluorite-structured solid solutions with trivalent cations.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Materials Science of Actinides (MSA)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- SC0001089
- OSTI ID:
- 1064907
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 17; Related Information: MSA partners with University of Notre Dame (lead); University of California, Davis; Florida State University; George Washington University; University of Michigan; University of Minnesota; Oak Ridge National Laboratory; Oregon state University; Rensselaer Polytechnic Institute; Savannah River National Laboratory; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)
- Country of Publication:
- United States
- Language:
- English
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