2015/05/01 by Hyowon Park, Andrew J. Millis, Park, Hyowon +3 · 2 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced Chemical Physics Studies #FOS: Physical sciences #Inorganic Chemistry and Materials #Machine Learning in Materials Science #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.1505.00227
openalex publication_date 2015/05/01 · openalex created_date 2022/10/07 · openalex updated_date 2026/07/28
Modern extensions of density functional theory such as the density functional\ntheory plus U and the density functional theory plus dynamical mean-field\ntheory require choices, including selection of variable (charge vs spin\ndensity) for the density functional and specification of the correlated\nsubspace. This paper examines these issues in the context of the "plus U"\nextensions of density functional theory, in which additional correlations on\nspecified correlated orbitals are treated using a Hartree-Fock approximation.\nDifferences between using charge-only or spin-density-dependent\nexchange-correlation functionals and between Wannier and projector-based\ndefinitions of the correlated orbitals are considered on the formal level and\nin the context of the structural energetics of the rare earth nickelates. It is\ndemonstrated that theories based on spin-dependent exchange-correlation\nfunctionals can lead to large and in some cases unphysical effective on-site\nexchange couplings. Wannier and projector-based definitions of the correlated\norbitals lead to similar behavior near ambient pressure, but substantial\ndifferences are observed at large pressures. Implications for other beyond\ndensity functional methods such as the combination of density functional and\ndynamical mean field theory are discussed.\n