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Method for locating low-energy solutions within DFT+U

Meredig, B. and Thompson, A. and Hansen, H. A. and Wolverton, C. and van de Walle, A. (2010) Method for locating low-energy solutions within DFT+U. Physical Review B, 82 (19). Art. No. 195128. ISSN 1098-0121. http://resolver.caltech.edu/CaltechAUTHORS:20110105-131905788

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Abstract

The widely employed DFT+U formalism is known to give rise to many self-consistent yet energetically distinct solutions in correlated systems, which can be highly problematic for reliably predicting the thermodynamic and physical properties of such materials. Here we study this phenomenon in the bulk materials UO_2, CoO, and NiO, and in a CeO_2 surface. We show that the following factors affect which self-consistent solution a DFT+U calculation reaches: (i) the magnitude of U; (ii) initial correlated orbital occupations; (iii) lattice geometry; (iv) whether lattice symmetry is enforced on the charge density; and (v) even electronic mixing parameters. These various solutions may differ in total energy by hundreds of meV per atom, so identifying or approximating the ground state is critical in the DFT+U scheme. We propose an efficient U-ramping method for locating low-energy solutions, which we validate in a range of test cases. We also suggest that this method may be applicable to hybrid functional calculations.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1103/PhysRevB.82.195128 DOIUNSPECIFIED
http://link.aps.org/doi/10.1103/PhysRevB.82.195128PublisherUNSPECIFIED
Additional Information:© 2010 The American Physical Society. Received 15 August 2010; revised 3 November 2010; published 22 November 2010. The authors gratefully acknowledge funding provided by the Sunshine to Petrol Grand Challenge at Sandia National Laboratories; the Department of Energy under NERI-C Grant No. DE-FG07-07ID14893; and the NSF under Grant No. DMR-0907669. This invention was made with Government support under and awarded by DoD, Army Research Office, 32 CFR 168a. Some of the calculations in this work were performed on the Quest high-performance computing cluster at Northwestern University. Teragrid resources provided by NCSA under Grant No. DMR050013N. The authors wish to thank M. Asta, V. Ozoliņš, and F. Zhou for helpful discussions and feedback on this manuscript.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG07-07ID14893
NSFDMR-0907669
Department of Defense (DOD)32 CFR 168a
Sandia National Laboratories Sunshine to Petrol Grand ChallengeUNSPECIFIED
National Center for Supercomputing Applications (NCSA) DMR050013N
Classification Code:PACS: 71.15.Mb, 71.15.Dx, 71.20.Be, 71.27.+a
Record Number:CaltechAUTHORS:20110105-131905788
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20110105-131905788
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21607
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:05 Jan 2011 21:27
Last Modified:26 Dec 2012 12:49

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