Abstract
Inelastic x-ray scattering measurements of the phonon density of states (DOS) of PuO2(+2%Ga) were made and compared to recent predictions from the literature made using three leading theoretical approaches; Density Functional Theory (DFT), DFT plus the Hubbard U (DFT+U), and Dynamical Mean-Field Theory (DMFT). The DFT prediction, which does not account for strong electronic correlations, underestimates the measured energies of most features. The DFT+U and DMFT predictions, which include approximations to strong correlation effects, more accurately reflect the low energy features but exaggerate splitting in the highest energy optic oxygen modes. The exaggeration of the splitting is worse for DFT+U than for DMFT. The transverse acoustic mode shows the least sensitivity to calculation type, and is well reproduced by all three theories. The longitudinal acoustic mode, which is thought to control the thermal conductivity, is more sensitive to calculation type, suggesting an important role for electronic correlations in making application-critical predictions.
Original language | English |
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Title of host publication | Actinides and Nuclear Energy Materials |
Pages | 141-147 |
Number of pages | 7 |
DOIs | |
State | Published - 2012 |
Externally published | Yes |
Event | 2012 MRS Spring Meeting - San Francisco, CA, United States Duration: Apr 9 2012 → Apr 13 2012 |
Publication series
Name | Materials Research Society Symposium Proceedings |
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Volume | 1444 |
ISSN (Print) | 0272-9172 |
Conference
Conference | 2012 MRS Spring Meeting |
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Country/Territory | United States |
City | San Francisco, CA |
Period | 04/9/12 → 04/13/12 |
Funding
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52–07NA27344. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The construction of HERIX was partially supported by the NSF under Grant No. DMR-0115852.