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Title: Mechanical and electronic properties of CeO{sub 2}, ThO{sub 2}, and (Ce,Th)O{sub 2} alloys

Abstract

A systematic first-principle study is conducted to calculate bulk modulus, elastic constants, phonon-dispersion curves, and electronic structures of CeO{sub 2}, ThO{sub 2}, and their ordered binary alloys Ce{sub x}Th{sub 8-x}O{sub 16} with x=1, 2, 4, 6, and 7 using local-density approximation (LDA), generalized gradient approximation (GGA), LDA+U, and GGA+U approaches. In order to get accurate results for these type of systems including f electrons [Ce(4f) and Th(5f)] we optimized the U parameter for use in LDA+U and GGA+U approaches. The computed structural, mechanical, and electronic properties of CeO{sub 2} and ThO{sub 2} are observed to display strong correlation with experimental data. In particular, the best agreement with experiment is obtained within the LDA+U in which on-site Coulomb interaction parameter (U{sub eff}) for Ce and Th are taken as 6.0 and 5.0 eV. To check the stability of alloy forms, phonon-dispersion curves of Ce{sub x}Th{sub 8-x}O{sub 16} with x=2, 4, and 6 are computed. In all concentrations, mechanical stability conditions are satisfied for alloys. Furthermore, we observed no negative phonon branches in the phonon spectrum of alloys. Our calculations indicated a strong effect of concentration, x, on the electronic structure of Ce{sub x}Th{sub 8-x}O{sub 16}.

Authors:
;  [1]
  1. Department of Chemical Engineering and Material Science and Engineering, Texas A and M University, College Station, Texas 77845-3122 (United States)
Publication Date:
OSTI Identifier:
21287036
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 80; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevB.80.014108; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; APPROXIMATIONS; BINARY ALLOY SYSTEMS; CERIUM ALLOYS; CERIUM OXIDES; CORRELATIONS; DENSITY FUNCTIONAL METHOD; DISPERSION RELATIONS; DISPERSIONS; ELECTRICAL PROPERTIES; ELECTRONIC STRUCTURE; ELECTRONS; INTERACTIONS; MECHANICAL PROPERTIES; OXIDES; PHONONS; SIMULATION; SPECTRA; STABILITY; THORIUM ALLOYS; THORIUM OXIDES

Citation Formats

Sevik, C, and Cagin, T. Mechanical and electronic properties of CeO{sub 2}, ThO{sub 2}, and (Ce,Th)O{sub 2} alloys. United States: N. p., 2009. Web. doi:10.1103/PHYSREVB.80.014108.
Sevik, C, & Cagin, T. Mechanical and electronic properties of CeO{sub 2}, ThO{sub 2}, and (Ce,Th)O{sub 2} alloys. United States. doi:10.1103/PHYSREVB.80.014108.
Sevik, C, and Cagin, T. Wed . "Mechanical and electronic properties of CeO{sub 2}, ThO{sub 2}, and (Ce,Th)O{sub 2} alloys". United States. doi:10.1103/PHYSREVB.80.014108.
@article{osti_21287036,
title = {Mechanical and electronic properties of CeO{sub 2}, ThO{sub 2}, and (Ce,Th)O{sub 2} alloys},
author = {Sevik, C and Cagin, T},
abstractNote = {A systematic first-principle study is conducted to calculate bulk modulus, elastic constants, phonon-dispersion curves, and electronic structures of CeO{sub 2}, ThO{sub 2}, and their ordered binary alloys Ce{sub x}Th{sub 8-x}O{sub 16} with x=1, 2, 4, 6, and 7 using local-density approximation (LDA), generalized gradient approximation (GGA), LDA+U, and GGA+U approaches. In order to get accurate results for these type of systems including f electrons [Ce(4f) and Th(5f)] we optimized the U parameter for use in LDA+U and GGA+U approaches. The computed structural, mechanical, and electronic properties of CeO{sub 2} and ThO{sub 2} are observed to display strong correlation with experimental data. In particular, the best agreement with experiment is obtained within the LDA+U in which on-site Coulomb interaction parameter (U{sub eff}) for Ce and Th are taken as 6.0 and 5.0 eV. To check the stability of alloy forms, phonon-dispersion curves of Ce{sub x}Th{sub 8-x}O{sub 16} with x=2, 4, and 6 are computed. In all concentrations, mechanical stability conditions are satisfied for alloys. Furthermore, we observed no negative phonon branches in the phonon spectrum of alloys. Our calculations indicated a strong effect of concentration, x, on the electronic structure of Ce{sub x}Th{sub 8-x}O{sub 16}.},
doi = {10.1103/PHYSREVB.80.014108},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 1,
volume = 80,
place = {United States},
year = {2009},
month = {7}
}